JP2863642B2 - Hard substrate coating device - Google Patents

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 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 red color mosaic liquid having a photoresist function is uniformly applied to a glass substrate on which a transparent electrode has been formed in advance, and then exposed to a color corresponding to red.
The mosaic is cured and excess liquid is removed to form a red color mosaic. The same processing is repeated for other colors such as green and blue. When applying a coating liquid to be a photoresist in this way,
This liquid needs to be strictly controlled to a uniform thickness (for example, about 2 μ ± 5%) and to be applied thinly. 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. In this spin coater, a coating liquid is dropped near a rotation center of a rotated substrate, and the liquid is applied by scattering using a centrifugal force. However, in the method using the spin coater, not only the time and labor efficiency for replacing the substrate are deteriorated, but also the amount of the liquid scattered and discarded increases. For this reason, there was a problem that the cost was 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, the surface of the nip roller is covered with rubber or the like, but static electricity accumulates on the surface of the nip roller as the number of coated substrates increases. Conventional rubber having a volume resistivity of about 10 ¹² Ωcm is generally used, and in this case, the charged voltage due to static electricity is about -8 KV just by passing 5 to 8 glass substrates. For this reason, there has been a problem that small droplets of the coating liquid are sucked and adhered to the nip roller from the micro rod bar, and stain the back surface of the substrate.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is directed to a case in which a coating liquid is applied to the lower surface of a substrate by a micro rod bar while a hard substrate is sandwiched between a micro rod bar and a nip roller. Another object of the present invention is to provide a hard substrate coating apparatus capable of preventing static electricity from accumulating on a nip roller, preventing a coating liquid from being adsorbed to a nip roller from a micro rod bar, and preventing a back surface of a substrate from being stained. And

[0007]

According to the present invention, there is provided a micro rod bar which is horizontally immersed in a coating solution tank while leaving its upper part,
In a hard substrate coating apparatus that applies a coating liquid to the lower surface of the hard substrate by nipping and sending the hard substrate between a nip roller disposed above the micro rod bar,
The volume resistivity of the surface material of the nip roller is 10 ⁶ Ωc
m or less, and rolling contact with the nip roller
Conductive static elimination bar that removes static electricity from the nip roller surface
The present invention is achieved by a hard substrate coating apparatus characterized in that:

[0008]

The coating liquid is always supplied to the coating liquid tank at a constant liquid level, and the coating liquid is always supplied to the surface of the micro rod bar immersed horizontally except for the upper part. A nip roller is opposed above the micro rod bar with a slight gap. The hard substrate is guided to the gap between the micro rod bar and the nip roller by a roller conveyor or the like, and is sent between the gaps. At this time, the coating liquid is applied to the lower surface of the substrate on which the micro rod bar is pressed.

The nip roller in contact with the upper surface of the substrate generates static electricity due to the contact with the substrate. The surface of the nip roller has a volume resistivity set to 10 ⁶ Ωcm or less .
Further, since a conductive static elimination bar is in rolling contact with the nip roller , static electricity is satisfactorily released and does not accumulate on the surface. Therefore, even if the micro rod bar faces the nip roller after passing through the substrate, the application liquid is not sucked from the micro rod bar to the nip roller and adheres.

[0010]

FIG. 1 is an overall route diagram of an embodiment of the present invention, and FIG.
3 is a plan view of the coating portion, FIG. 3 is a front sectional view thereof, FIGS. 4 and 5 are end views taken along lines IV-IV and VV in FIG.
FIG. 6 is a conceptual diagram of the entire arrangement.

In FIG. 6, reference numeral 10 denotes a glass substrate;
Is a roller conveyor, and the glass substrate 10 is sent from left to right in the figure with the left and right edges of the lower surface thereof placed on rollers of the conveyor 12. In the middle of the conveyor 12, the coating unit 14
Are arranged. The coating unit 14 includes a microrod bar 16 having a small diameter and a circular cross section, a nip roller 18 having a large diameter opposed to the microrod bar 16, and a coating liquid tank 20 into which almost the entirety of the microrod bar 16 is left except for the upper part.

The nip roller 18 is made of a material whose surface has a volume resistivity of 10 ⁶ Ωcm or less, for example, a conductive rubber 18.
a (see FIGS. 3 and 6). Normally 10 ⁵
Those having a volume resistivity of Ωcm or less are called conductive rubber. Here, the volume resistivity means the volume resistance per unit area and unit thickness. In the nip roller 18, the inside of the conductive rubber 18a on the surface is made of metal, and the static electricity accumulated in the conductive rubber is grounded to the frame of the apparatus through the metal portion 18b and released.

The nip roller 18 applies a predetermined clamping force to the glass substrate 10 in a state where the glass substrate 10 is sandwiched between the nip roller 18 and the micro rod bar 16.
Oppose. In FIG. 6, reference numeral 102 denotes rolling contact with the nip roller 18.
Nip roller
This is to remove static electricity from the surface of the rubber 18. Ie
The static elimination bar 102 covers a part of the surface in the circumferential direction over the entire width.
And the other parts are made of rubber 106
It is a thing.

As shown in FIGS. 2 to 5, the coating liquid tank 20 has a long and shallow liquid reservoir 22 in a direction perpendicular to the direction in which the substrate 10 is fed.
4, while the coating liquid is discharged from the liquid discharge port 26. The liquid supply pipe 24 faces above a concave portion 28 (FIGS. 2 and 5) provided on an inner wall near one end of the liquid reservoir 22.
The drain port 26 opens at the bottom near the other end. Therefore, the coating liquid is suitable for flowing in the liquid reservoir 22 in the longitudinal direction thereof to homogenize the liquid. The depth of the coating liquid is monitored by a liquid level sensor (not shown), and is constantly maintained at a constant level.

The micro rod bar 16 is held horizontally so that its upper part is exposed from the liquid. That is, bearing portions 30 and 32 having concave portions that open upward in a semicircular arc are provided at both ends of the liquid reservoir portion 22, and the bearing portions 30 and 32 are provided.
The micro rod bar 16 is rotatably held between the cap and the caps 34 and 36 covered from above. The intermediate portion of the micro rod bar 16 is supported from below by a backup member 38. The backup member 38 is made of a hard synthetic resin having excellent slidability. A semicircular groove formed on the upper surface of the backup member 38 along the longitudinal direction comes into contact with the micro rod bar 16 from below, and the micro rod bar 16 To prevent deflection. The height of the backup member 38 can be finely adjusted from the lower surface of the coating liquid tank 20 by a number of adjustment screws 40 arranged below the backup member 38.

One end (the end on the rear side in FIG. 6) of the micro rod bar 16 is projected rearward by the coating solution tank 20, and this projected end is connected to the electric motor 44 by a detachable joint 42.
It is connected to the. The electric motor 44 is mounted on the glass substrate 1
The rotation is controlled so that the feed speed of 0 is equal to the speed of the conveyor 12.

Therefore, the glass substrate 10 sent from the left to the right in FIG. 6 by the roller conveyor 12 enters between the micro rod bar 16 and the nip roller 18. Since the application liquid in the liquid reservoir 22 is attached to the surface of the micro rod bar 16 by the rotation thereof, the application liquid is applied to the lower surface of the glass substrate 10 with the rotation of the micro rod bar 16. The level of the liquid in the liquid reservoir 22;
Since the holding pressure by the nip roller 18 is controlled to be constant, the thickness of the liquid applied to the lower surface of the glass substrate 10 can be controlled to be sufficiently thin and highly accurate. After the substrate 10 has passed, the nip roller 18 faces the micro rod bar 16 with a slight gap. Here, the surface of the nip roller 18 is set to a predetermined volume resistivity or less as described above , and the static elimination bar 102 is in rolling contact with the nip roller 18, so that static electricity enough to suck the application liquid on the surface of the micro rod bar 16 is not accumulated. . Therefore, the coating liquid does not adhere to the nip roller 18.

Next, a liquid supply system, a drainage system and a circulation system of the coating liquid tank 20 will be described. In FIGS. 1 and 6,
Reference numeral 50 denotes a liquid supply tank for storing a new coating liquid, and reference numeral 52 denotes a drainage tank. The liquid levels of these tanks 50, 52 are detected by, for example, capacitance type liquid level sensors 54, 56,
When the liquid level falls below or above a predetermined liquid level, the controller 58 instructs replenishment of the liquid or discard of the discharged liquid, or instructs to stop the entire apparatus.

In the liquid supply system of this embodiment, the liquid is supplied under pressure by pressurizing the liquid supply tank 50. That is, the gas pressure supplied from the pressure gas cylinder 60 such as nitrogen gas is regulated by the regulator 62, and is passed through the solenoid valve 64, the check valve 66, the regulator 68 or 70, the electromagnetic three-way switching valve 72, and the air filter 74. To the liquid supply tank 50. The regulators 68 and 70 have different set pressures, and one of the set pressures is selected by the switching valve 72.
The liquid supply tank 50 is made airtight, and pressurizes the inside of the tank 50 to pump the coating liquid therein to the liquid supply pipe A.

The supply pipe A has a two-port two-position switching valve 76, a supply pipe B, a filter 78, a supply pipe C,
And another switching valve 80 are sequentially connected, and are led to a liquid supply pipe 24 provided in the coating section 14 by a liquid supply pipe D. The downstream side of the filter 78 is connected to the drainage tank 52 by the drainage pipe E via the drainage pipe E and the switching valve 82.

The circulation system includes a circulation pipe G connected to the drain port 26 of the coating section 14, a diaphragm circulation pump 84, and a circulation pipe H connecting the pump 84 to the liquid supply pipe B. Prepare. And the filter 78 and the switching valve 8
0 and the liquid supply pipes C and D are also used as a liquid supply system. The pump 84 is driven by gas pressure, and the gas pressure is guided from the pump 60 through a regulator 86, a solenoid valve 88, and a manual throttle control valve 90. Therefore, this control valve 90
Thereby, the operation speed of the pump 84 is controlled, and the circulation flow rate of the liquid can be controlled. The circulation pipe G branches off, and the drainage tank 52 is switched via the switching valve 92 and the drainage pipe I.
It is connected to the.

The liquid in the liquid supply tank 50 can be discharged to the outside by a switching valve 94. The switching valves 76, 80, 82, 92, 94 are driven by the gas pressure of the cylinder 60. That cylinder 60 of the gas pressure regulated by the regulator 96 _V 1 the solenoid valves from ~V ₅
Are distributed to the respective switching valves 76, 80, 82, 92, 94. The solenoid valves V _{1 to} V ₅ , 64 and the switching valve 72
It is controlled by the controller 58. Each solenoid valve V ₁
~V _5, 64, switching valve 74, such as an electromagnetic valve 88 is housed in the housing portion 98 shown in FIG. Switching valves 76, 8
The 0, 82 filter 78, the pump 84, and the throttle control valve 90 are combined into one unit 100 (see FIG. 1) and can be attached to and detached from the front of the apparatus.

Next, the operation of the liquid supply, drainage and circulation system will be described. First, when supplying new liquid, the switching valves 82, 92 and 94 of the drainage system are closed, and the electromagnetic valve 88 is closed to stop the circulation pump 84. When the solenoid valve 64 is opened, the regulator 68 determined by the three-way switching valve 72,
A gas having any one of the set pressures 90 is guided to the liquid supply tank 50. Therefore, new liquid is pushed up to the pipe A.
When the switching valves 76 and 80 are opened, the liquid is filtered by the filter 78 and supplied to the coating liquid tank 20 of the coating unit 14. Signal indicating the liquid level is input to the controller 58, when a predetermined liquid level, the controller 58 closes the switching valve 76 via the solenoid valve V _1, actuating the circulation system to open the solenoid valve 88. That is, when the electromagnetic valve 88 is opened, the pump 84 is started, and the coating liquid in the coating liquid tank 20 is supplied to the pipe G and the pump 8.
4, pipes H and B, filter 78, pipe C, switching valve 8
0, circulate through pipe D. Therefore, dust and the like in the liquid are removed by the filter 78.

[0024] In this embodiment forms the surface of the nip roller 18 of the following materials given volume resistivity, other rollers for neutralization to bordered rolling on the surface of the nip roller 18 i.e.
The static elimination bar 102 (FIG. 6) is partially full-width in the circumferential direction of the surface .
Over the metal 104 and the other with the rubber 106
I have. In this case, a table of the rubber 106 is further provided.
Apply a sticky substance to the surface, and
Mi may be removed. Further, the static elimination bar 102
Is the entire surface formed by the metal, be configured to dissipate static electricity nip roller 18 to the frame of the apparatus
No.

[0025]

As described above, according to the present invention, when a hard substrate is sandwiched between a micro rod bar and a nip roller and fed to the lower surface of the substrate with the micro rod bar, the volume of the surface of the nip roller is reduced. The resistivity was set to 10 ⁶ Ωcm or less, and a static elimination bar was roll-contacted to the nip roller . Therefore, static electricity does not excessively accumulate on the surface of the nip roller, and the coating liquid is not attracted to the nip roller from the surface of the micro rod bar facing the static electricity. Therefore, the back surface of the substrate is not stained with the coating liquid.

[Brief description of the drawings]

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

FIG. 2 is a plan view of a coating unit.

FIG. 3 is a front sectional view

FIG. 4 is an end view taken along the line IV-IV in FIG. 3;

FIG. 5 is an end view taken along line VV in FIG. 3;

FIG. 6 is a conceptual diagram of the entire arrangement.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Glass substrate 14 Coating part 16 Micro rod bar 18 Nip roller 20 Coating liquid tank 102 Static elimination bar (static elimination roller)

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masafumi Ozaki 1005 Koizono, Ayase-shi, Kanagawa Prefecture Inside Fuji Mai Chromaix Co., Ltd. (56) References JP-A-4-110058 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05C 1/00-1/16 G03F 7/16

Claims (1)

(57) [Claims] 1. A hard substrate is sandwiched and sent between a micro rod bar immersed horizontally leaving an upper part in a coating liquid tank and a nip roller disposed above the micro rod bar, whereby in hard substrate coating apparatus for applying a coating solution on the lower surface of the hard substrate, the volume resistivity of the surface material of the nip roller while the 10 ⁶ [Omega] cm or less, the two
Rolls on the nip roller to reduce the static electricity on the nip roller surface.
A hard substrate coating apparatus comprising a conductive static elimination bar for removal .