JP2889713B2 - 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 (so-called Gieser) 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. However, in this case, it is unavoidable that dust such as extremely fine cutting chips cut around the glass substrate is mixed into the coating liquid. For this reason, after a certain number of treatments, it is necessary to discard all of the liquid in the coating liquid tank and replace it with a new liquid. Therefore, there is a problem that not only the consumption of the liquid increases but also the operation rate of the apparatus decreases. In addition, the micro rod bar dries while all liquids are drained and replaced, making the application of the first few substrates unstable after adding new liquids and reducing product yield. There was also.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and when the coating liquid is applied to the lower surface of the substrate while the hard substrate is interposed between the upper and lower rollers, the consumption of the coating liquid is reduced. It is an object of the present invention to provide a hard substrate coating apparatus capable of reducing the number of operations, increasing the operation rate of the apparatus, and improving the product yield without causing drying of the micro rod bar due to liquid exchange.

[0006]

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,
A liquid level sensor for monitoring the coating liquid depth of the coating liquid tank;
Supply a new coating liquid to the coating liquid tank and read out the liquid level sensor.
A liquid supply system that keeps the coating liquid depth constant based on the force and this liquid supply
A circulation system that operates while the system is not operating to circulate the coating liquid in the coating liquid tank, and a drainage system that discharges the coating liquid in the coating liquid tank
And a filter provided in the circulation system and the liquid supply system for removing dust in the application liquid, and is provided by a hard substrate application apparatus. Here, the filter of the circulation system can also be used as a filter provided in the liquid supply system .

[0007]

[Function] A new coating liquid is supplied by the liquid supply system to
The sa detects that the greaser coating liquid depth has become constant.
Then, the liquid supply system is stopped and the circulation system is started. others
The coating solution of Meguisa circulates through a circulating filter. Therefore, even if dust adhering to the substrate is mixed into the coating liquid via the micro rod bar, the dust is removed by this filter. Therefore, a clean coating solution can always be applied to the substrate.

[0008]

FIG. 1 is an overall route diagram of an embodiment of the present invention, and FIG.
Is a plan view of the gisa, FIG. 3 is a front sectional view thereof, and FIG.
5 is an end view taken along the line IV-IV in FIG. 3 and an end view taken along the line VV in FIG. 3, and FIG.

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. Gieser 1 in the middle of the conveyor 12
4 are provided. The gisa 14 includes a microrod bar 16 having a small diameter and a circular cross section, a nip roller 18 having a large diameter facing above the microrod bar 16, and a coating solution tank 20 in which almost the entirety of the microrod bar 16 except the upper portion is contained.

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 is viewed above a concave portion 28 (FIGS. 2 and 5) provided on the inner wall near one end of the liquid reservoir 22, and 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.

The surface of the nip roller 18 is made of conductive rubber, and is held so as to apply a predetermined clamping force to the glass substrate 10 with the glass substrate 10 sandwiched between the nip roller 18 and the micro rod bar 16.

Accordingly, 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.

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 inside of 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 liquid supply pipe A has a two-port two-position switching valve 76, a liquid supply pipe B, a filter 78, a liquid supply pipe C,
And another switching valve 80 are sequentially connected, and are led by a liquid supply pipe D to a liquid supply pipe 24 provided in the gheeser 14. 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 gieser 14, a diaphragm circulation pump 84, and a circulation pipe H connecting the pump 84 to the liquid supply pipe B. . The filter 78, the switching valve 80, and the liquid supply pipes C and D also serve 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 9
With 0, 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 gas cylinder 60 is distributed to each switching valve 76,80,82,92,94 via the solenoid valves V ₁ ~V ₅ from pressure regulated by the regulator 96. Solenoid valve V ₁ ~V _5, 64 and the switching valve 72 is controlled by the controller 58. Each solenoid valve V ₁ ~V _5,
64, the switching valve 74, the solenoid valve 88, etc.
8 is housed. The switching valves 76, 80, 82, the 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 gieser 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.

In this embodiment, the filter of the circulation system also serves as the filter 78 of the liquid supply system, so that only one filter is required. However, the present invention may, of course, be used separately. is there.

[0022]

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, the micro rod bar is immersed horizontally while leaving the upper part thereof. Since the liquid is circulated and a filter is provided in the circulation system, the coating liquid in the coating liquid tank can be always kept clean. For this reason, the consumption of the coating liquid can be reduced. Further, since it is not necessary to stop the apparatus as in the case where the coating liquid in the coating liquid tank is completely discarded, the operation rate of the apparatus is improved.

The coating liquid depth is monitored by a liquid level sensor and is constant.
Stop the circulation system until the depth reaches
At a certain depth, stop the liquid supply system and activate the circulation system.
Control the coating liquid depth with high accuracy.
You. Therefore, the coating thickness can be controlled with high accuracy.
In addition, dry the micro rod bar for liquid exchange.
Product yield is also improved.
1). Here, the filter of the circulation system can be used also as the filter of the liquid supply system. In this case, the number of filters is reduced, which is preferable (claim 2).

[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 Gieser.

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 Gieser 16 Micro rod bar 18 Nip roller 20 Coating liquid tank 78 Filter 84 Circulation pump G, H Circulation pipe, B, C, D Liquid supply pipe which becomes a part of circulation system

──────────────────────────────────────────────────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-2-25881 (JP, A) JP-A-60-58279 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05C 1/00-1 / 16 B05C 11/10 G03F 7/16

Claims (2)

(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 a hard substrate coating apparatus for coating a coating liquid on the lower surface of a hard substrate , the coating liquid depth of the coating liquid tank is
A liquid level sensor to monitor and a new coating liquid in the coating liquid tank
Supply and keep the coating liquid depth constant based on the output of the liquid level sensor
A circulating system that operates while the liquid supply system is not operating to circulate the coating liquid in the coating liquid tank;
A drainage system for discharging the coating liquid, the circulation system and the supply
A hard substrate coating apparatus, comprising: a filter provided in the liquid system to remove dust in the coating liquid. Wherein said liquid supply system filters hard substrate coating device according to claim 1 which is shared with the circulatory system of the filter.