JPH0929150A - Hard substrate coater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the accumulation of static electricity and excessive contact pressure by forming a nip roller for nipping and sending a hard substrate along with a microrod bar into the multistage structure consisting of the core bar, elastic layer and surface layer and forming the surface layer from a rubber material with the volume resistivity specified. SOLUTION: A microrod bar 14 is placed on a backup material provided in a coating soln. tank 12 and driven by a motor. Meanwhile, both left and right edges of a glass substrate 10 are placed on a conveyor roller 22, and the front edge is allowed to intrude into the space between the microrod bar 14 and nip roller 20. The substrate 10 is conveyed at a fixed speed, and the lower face of the substrate 10 is coated with the soln. by the microrod bar 14. In such a hard substrate coater, the nip roller 20 is formed into the multilayer structure consisting of a metallic columnar core bar 20A, an elastic layer 20B on the surface and a surface layer 20C covering the surface. At this time, the elastic layer 20C is formed from a rubber material having <=10<5> Ωcm volume resistivity.

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 used for manufacturing a liquid crystal display panel and the like using a glass substrate and for applying a coating liquid such as a photoresist to a hard substrate in a thin and uniform manner. is there.

[0002]

2. Description of the Related Art In a manufacturing process of a liquid crystal plate, there is a process of applying a coating liquid such as a photoresist to a thin and uniform thickness on a hard substrate such as a glass substrate. For example, in the production of a color liquid crystal plate, a transparent electrode is formed on a glass substrate in advance,
After uniformly applying a red color mosaic liquid having the function of a photoresist, the color mosaic corresponding to the red color is cured by exposure, and an excess liquid is removed to form a red color mosaic. . The same processing is repeated for other colors such as green and blue. When a coating liquid to be a photoresist is applied as described above, it is necessary to strictly control this liquid to a uniform thickness (for example, about 2 μ ± 5%) and to apply the thin liquid. This is because if the thickness of the coating is non-uniform, the light transmittance becomes uneven, which leads to a deterioration in quality.

Conventionally, a spin coater has been used for this coating. This spin coater is one in which a coating liquid is dropped near the center of rotation of a rotated substrate and the liquid is scattered by utilizing centrifugal force to apply the liquid. However, in the method using this spin coater, not only the labor efficiency for replacing the substrate is deteriorated but also the amount of the liquid scattered and discarded increases. Therefore, there is a problem that the cost is increased.

In view of this, it has been considered to use an apparatus for coating a substrate between a pair of upper and lower rollers disposed horizontally. In this device, the lower part of the micro rod bar, which is the lower roller, is immersed in the coating solution, and the substrate is sandwiched between the micro rod bar and the nip roller located above the micro rod bar. It is to be applied.

Here, in the conventional apparatus, the gap between the nip roller and the micro rod bar is kept constant, and when a hard substrate having a constant thickness enters between them, a predetermined sandwiching pressure (referred to as nip pressure) is applied to the hard substrate. Was doing. Needless to say, it is necessary to prevent the coating liquid from adhering to the nip roller by providing a slight gap between the two when the hard substrate is not sandwiched.

[0006]

2. Description of the Related Art Here, the nip roller has a cylindrical cored bar whose surface is covered with a rubber layer. However, static electricity accumulates when a hard substrate is applied. It is considered that this static electricity is due to charging (referred to as peeling charging) that occurs when the nip roller separates from the hard substrate.

When the nip roller is charged by the peeling charging, small droplets or splashes of the coating liquid adhere to the nip roller from the micro rod bar. Therefore, there arises a problem that the back surface (non-coated surface) of the hard substrate becomes dirty. Further, when the end of the hard substrate escapes from between the microrod bar and the nip roller, the static electricity of the nip roller causes the coating liquid to flow around from the end of the hard substrate to the back surface (top surface) and contaminate the vicinity of the end of the hard substrate. It was

Therefore, it is considered that the conductivity of the nip roller is improved so that the static electricity can be quickly released to the core metal. For example, it is conceivable that the rubber layer on the surface is made of highly conductive rubber. However, rubber having good conductivity generally needs to contain a large amount of carbon, and therefore has a property of becoming hard. If the rubber of the rubber layer is hard, the contact pressure (nip force) on the hard substrate increases, and the microrod bar easily scratches the hard substrate.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and prevents static electricity from accumulating on the nip roller, while the contact pressure (nip force) against the hard substrate does not become excessive and the microrod bar is hardened. An object of the present invention is to provide a hard substrate coating device that does not damage the substrate.

[0010]

According to the present invention, for this purpose, a hard substrate is sandwiched between a microrod bar whose lower portion is immersed in a coating liquid tank and a nip roller which is arranged above the microrod bar so as to be fed. As a result, in the hard substrate coating apparatus for coating the coating liquid on the lower surface of the hard substrate, the nip roller has a multilayer structure including a core metal, an elastic layer and a surface layer, and the surface layer has a volume resistivity of 10 ⁵ Ωcm or less. And a hard substrate coating device characterized by being formed of a rubber material.

That is, while the conductivity of the rubber layer itself is improved, even if the rubber layer is hardened as a result, the contact pressure is prevented from becoming excessive by making the underlying layer soft as an elastic layer.

Another object of the present invention is to improve the conductivity of the rubber layer of the nip roller by providing an ion wind generator for supplying ion wind on the surface of the nip roller so that the charged electric charge on the surface of the nip roller is removed by the ion wind. You may In this case, the nip roller has a multilayer structure in which an elastic layer is interposed below the surface layer, and the surface layer rubber has a volume resistivity of 10%.
If it is ⁵ Ωcm or less, the removal of the charged electric charge becomes more reliable.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall layout view of an embodiment of the present invention, FIG. 2 is a perspective view of its coating portion, and FIG. 3 is a sectional view of a nip roller.

1 and 3, reference numeral 10 denotes a glass substrate used for a color filter of a liquid crystal plate, which is a hard substrate. The glass substrate 10 has a width of, for example, 300 to 5
00 mm, length 400-600 mm, thickness 0.7-1.
It is 1 mm.

Reference numeral 12 is a coating liquid tank, and 14 is a microrod bar. The micro rod bar 14 is formed by winding a thin metal wire, for example, a stainless wire, on the surface of a stainless steel rod having a circular cross section so as to be in close contact with the rod, and applying a liquid by utilizing a capillary phenomenon due to a groove between the metal wires. is there. The micro rod bar 14 is driven by a motor while being mounted on a backup material (not shown) provided in the coating liquid tank 12.

The liquid level of the coating liquid is controlled so that the lower part of the microrod bar 14 is sufficiently immersed. The outer diameter (diameter) of the micro rod bar bar 14 is about 12
mm. A nip roller 20 is held above the micro rod bar 14. The diameter of the nip roller 20 is about 150 mm in this embodiment. The diameter can be selected within the range of about 60 to 200 mm.

The glass substrate 10 is conveyed at a constant speed from the left side of FIGS. 2 and 3 with its left and right edges placed on the conveying roller 22, and its front edge enters between the microrod bar 14 and the nip roller 20. In FIG. 2, reference numeral 24 is a case for accommodating the drive mechanism of the transport roller 22.

Thereafter, the glass substrate 10 is fed to the right side at a constant speed by the rotation of the microrod bar 14 and the nip roller 20, and the microrod bar 1 is fed between them.
Therefore, the liquid is applied to the lower surface of the glass substrate 10. Then, the left and right edges of the glass substrate 10 on which the coating has been completed are placed on the transport rollers 22 and further fed to dry the coating liquid.

Next, the nip roller 20 will be described with reference to FIG. The nip roller 20 is a cylindrical metal core 20A made of metal.
And a surface layer 20C that covers the surface of the elastic layer 20B and an elastic layer 20B that is stacked on the surface of the cored bar 20. Here, the core metal 20A is, for example, SU that is hard to rust.
It is made of S (stainless) material, and its radius is about 60m.
m. The elastic layer 20B is made of, for example, the same material as the surface layer 20C, such as rubber, which has low hardness and is sufficiently soft, and has a thickness of about 12 mm.

The surface layer 20C is made of a material having good conductivity, for example, synthetic rubber having excellent solvent resistance such as EPDM and butyl rubber, and has a thickness of about 3 mm. The rubber of this surface layer has a volume resistivity Ρ of 10 ⁵ Ωcm or less. Here, the volume resistivity Ρ (Ωcm) is defined as follows. [Ρ = (πd
² / 4t) _Rv ] where d is the diameter (cm) of the main electrode, t
Is the thickness of the test piece (cm), and R _v is the volume resistance (Ω).

As described above, the rubber having good conductivity is hard because it contains a large amount of carbon, but the surface of the nip roller 20 can have sufficient elasticity by the action of the elastic layer 20B thereunder. Therefore, the contact pressure (nip force) on the glass substrate 10 can be reduced. This contact pressure is 2 kg
It is desirable to set it to f / cm ² or less. As a result of reducing the contact pressure of the nip roller 20 in this way, there is no possibility that the wire of the microrod bar 14 will scratch the glass substrate 10.

FIG. 4 is a conceptual diagram of another embodiment. In this embodiment, the charged charges on the surface of the nip roller are removed by ion wind. In this figure, 30 is a high voltage power source and 32 is an ionizing air bar, which forms an ion wind generator 34. The ionized air bar 32 is in the shape of a box that is long in the width direction of the nip roller 20 and has an opening on the surface facing the nip roller 20, and a large number of discharge needles are arranged at regular intervals in the length direction.

An alternating high voltage supplied from the high-voltage power supply 30 is applied between the adjacent discharge needles to generate corona discharge between the discharge needles. The ions generated by this discharge collide with gas molecules and the gas moves as a whole at a certain velocity to generate so-called ionic wind or electric wind. This ionic wind is introduced to the surface of the nip roller 20 to remove the charge on the surface of the nip roller 20. In this embodiment, the high voltage power supply 30 has four output terminals, and four ionized air bars 32 are arranged along the outer circumference of the nip roller 20.

If the nip roller 20 used in the embodiment of FIG. 4 has a multi-layered structure having the elastic layer 20B shown in FIG. 3, the effect of the ion wind is added to further increase the static elimination effect of the nip roller 20. To do. However, even if the nip roller has a conventional structure, that is, without the elastic layer 20B, the charged electric charge can be removed by using the ionic wind. The present invention includes such things.

[0025]

As described above, according to the first aspect of the present invention, the nip roller has a multi-layer structure composed of a cored bar, an elastic layer and a surface layer, and the surface layer has a volume resistivity of 10 ⁵ Ωcm or less and good conductivity. Since it is formed of a material, the electric charge that is charged on the nip roller by static electricity is quickly diffused by the surface layer over the entire surface of the nip roller and discharged to the cored bar through the elastic layer. For this reason, static electricity does not accumulate on the surface of the nip roller, and small droplets or splashes of the coating liquid do not adhere to the nip roller.

When the end of the hard substrate escapes from between the nip roller and the microrod bar, the coating liquid of the microrod bar is sucked up by the nip roller from the end of the hard substrate and spreads to the back surface (non-coated surface) of the hard substrate. It will not be crowded. Therefore, there is no possibility that the back surface or the terminal surface of the hard substrate is contaminated with the coating liquid.

If an ion wind generator for supplying ion wind to the surface of the nip roller is provided here, the electric charge on the surface of the nip roller can be removed by the ion wind (claim 2). As a result, the same effect as in claim 1 can be obtained. The nip roller may have a conventional structure, that is, it may have no elastic layer and the surface rubber layer may have poor conductivity. However, if the nip roller having the structure of claim 1 is used, the charge removal effect of the nip roller is further improved (claim 3).

[Brief description of drawings]

FIG. 1 is an overall layout diagram of an embodiment of the present invention.

FIG. 2 is a perspective view of the coating section.

FIG. 3 is a sectional view of a nip roller.

FIG. 4 is a diagram showing another embodiment.

[Explanation of symbols]

 10 Glass Substrate as Hard Substrate 12 Coating Liquid Tank 14 Micro Rod Bar 20 Nip Roller 20A Core Bar 20B Elastic Layer 20C Surface Layer 30 High Voltage Power Supply 32 Ionization Air Bar 34 Ion Wind Generator

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masafumi Ozaki 1005 Kozoen, Ayase City, Kanagawa Prefecture, Fuji Micrographix Co., Ltd. (72) Shinya Yamazaki, 1005 Koen, Ayase City, Kanagawa Prefecture, Fuji Micrologix Co., Ltd. (72) Inventor Hirofumi Kumagai 1005 Kozono, Ayase City, Kanagawa Prefecture Fuji Micrographix Co., Ltd.

Claims (3)

[Claims] 1. A hard substrate is sandwiched between a microrod bar whose lower portion is immersed in a coating liquid tank and a nip roller which is arranged above the microrod bar to face the lower surface of the hard substrate. In a hard substrate coating apparatus for coating a coating liquid, the nip roller has a multilayer structure including a core metal, an elastic layer and a surface layer, and the surface layer has a volume resistivity of 1
A hard substrate coating device formed of a rubber material having a resistance of 0 ⁵ Ωcm or less. 2. A hard substrate is sandwiched between a microrod bar whose lower portion is immersed in a coating liquid tank and a nip roller which is arranged above the microrod bar so as to feed it to the lower surface of the hard substrate. A hard substrate coating apparatus for applying a coating liquid, comprising an ion wind generator for supplying ion wind to the surface of the nip roller. 3. The hard substrate coating apparatus according to claim 1, further comprising an ion wind generator that supplies ion wind to the surface of the nip roller.