JP2003001171A - Coating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating device capable of applying a thin coating of a coating liquid to a base material utilizing a capillary action, eliminating a liquid tank for submerging a coating nozzle, and capable of conducting liquid contact and liquid separation quickly. SOLUTION: While moving a base material W with respect to a coating nozzle 14, the coating liquid is supplied to a capillary gap 16 of the coating nozzle 14 from a coating tank 22, and the height of the coating liquid in the coating tank 22 is adjusted. As a result, the coating liquid is brought into liquid contact with the lower face of the base material W from a discharge port 18. After finishing the coating until the predetermined position, the coating tank 22 is lowered and the liquid separation is conducted.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coating apparatus for coating a substrate with a coating liquid.

[0002]

2. Description of the Related Art Recently, liquid crystal display devices have come into widespread use, and it has become necessary to apply a coating liquid to a glass plate of this liquid crystal display device and a protective plate attached to the glass substrate.

As a method for applying a coating liquid to such a substrate such as a glass substrate, a coating apparatus utilizing a capillary phenomenon has been proposed (Japanese Patent Laid-Open No. 8-224528, Japanese Patent Laid-Open No. 6-224528).
-343908).

In this coating apparatus, a nozzle having a capillary gap is submerged inside a liquid tank filled with the coating liquid, and when coating, the nozzle is raised to raise the vicinity of the lower surface of the base material. The coating liquid is applied to the lower surface of the base material by contacting the coating liquid through the capillary gap.

[0005]

In the coating apparatus having the above-mentioned structure, since the capillary phenomenon is utilized, there is an effect that the coating liquid can be thinly applied to the base material.

However, in this coating apparatus,
Since it is necessary to fill the liquid tank with the coating liquid and to immerse the nozzle inside this, it is necessary to discard the coating liquid filled in the liquid tank after the coating is completed. However, the coating liquid used for the liquid crystal display device is very expensive, and it is necessary to effectively use this coating liquid even a little.

Further, since the nozzle is submerged in the liquid tank, when the nozzle is projected from the liquid tank, the coating liquid around the nozzle is solidified, and this portion needs to be cleaned. There is also a problem that when the nozzle is submerged in the liquid tank, the solidified coating liquid becomes an impurity.

[0008] Further, when the coating liquid is brought into contact with and released from the base material through the capillary gap, it takes a long time for this contact and release because it utilizes the capillary phenomenon. There were also problems.

In view of the above problems, therefore, the present invention makes it possible to thinly coat the coating liquid on the substrate by utilizing the capillary phenomenon, eliminates the liquid tank for submerging the nozzle, and separates it from the liquid contact. It is intended to provide a coating device capable of performing a liquid quickly.

[0010]

According to a first aspect of the present invention, there is provided a coating nozzle having a capillary gap, the upper end of which is a discharge port for the coating liquid and which extends in the left-right direction. While storing the coating liquid in, a coating liquid supply means that is in communication with the coating nozzle and can supply the coating liquid to the coating nozzle,
A moving means for relatively moving the surface to be coated of the base material in the front-back direction along the discharge port in a state where the coating nozzle is brought close to the base material to be coated; While moving the base material and the coating nozzle relative to each other by means, the coating liquid supplied from the coating liquid supply means to the coating nozzle is supplied from the discharge port of the coating nozzle to the base. The coating device is characterized in that the coated surface of the material is coated by a capillary phenomenon.

According to a second aspect of the present invention, the coating liquid supply means stores the coating liquid in a state of being open to the atmosphere, and the coating tank is relatively disposed with respect to the coating nozzle. The coating apparatus according to claim 1, further comprising: a coating tank vertical movement unit that moves up and down; and a liquid level detection unit that detects a liquid level height in the coating tank in a non-contact manner. .

According to a third aspect of the present invention, there is provided liquid level control means for controlling the liquid level height detected by the liquid level detection means to a value arbitrarily set by using the coating tank vertical movement means. The coating device according to claim 2.

According to a fourth aspect of the invention, the liquid level control means is
When the base material is located at the coating start position and the coating nozzle is in the vicinity of the base material, the liquid level height is relatively increased to the liquid contact height set value and a small amount 4. The coating apparatus according to claim 3, wherein the coating liquid is supplied to the coating nozzle to promote the liquid contact with the surface to be coated of the base material.

According to a fifth aspect of the present invention, the liquid level control means is
The coating apparatus according to claim 3, wherein the liquid surface height is maintained at a coating height set value while the coating liquid is applied to the surface to be coated of the base material.

According to a sixth aspect of the invention, the liquid level control means is
When the base material is located at the coating end position, the liquid level height is relatively lowered to the separation height setting value, and the coating liquid in contact with the surface to be coated of the base material is removed. The coating apparatus according to claim 3, wherein the coating apparatus is suctioned to promote syneresis.

According to a seventh aspect of the present invention, there is provided a coating liquid replenishing means for replenishing the coating liquid amount reduced from the coating tank, and the coating tank is always filled with the same coating liquid amount. The coating apparatus according to claim 2, which is characterized in that.

The invention of claim 8 is characterized in that the base material is a long base material, and a backup roll for conveying the base material in the front-rear direction is arranged above the coating nozzle. The coating apparatus according to claim 1.

According to a ninth aspect of the present invention, the base material is a plate-shaped base material, and a suction table for adhering the plate-shaped base material to a lower surface and transporting it in the front-rear direction is provided above the coating nozzle. The coating device according to claim 1, wherein the coating device is arranged in

According to the coating apparatus of claim 1, the coating liquid is stored in a bear which is open to the atmosphere while the base material and the coating nozzle are relatively moved by the moving means. The coating liquid is supplied from the supply means to the coating nozzle, and is applied to the surface to be coated of the base material from the discharge port of the coating nozzle by the capillary phenomenon.

According to the coating apparatus of claim 2, while detecting the liquid level in the coating tank by the liquid level detecting means without contact,
The coating tank up-and-down moving means moves the coating tank up and down relative to the coating nozzle, so that the surface to be coated of the base material is coated by a capillary phenomenon.

In the coating apparatus according to the third aspect, the liquid level control means controls the liquid level height detected by the liquid level detection means to a value arbitrarily set by using the coating tank vertical movement means.

According to a fourth aspect of the present invention, the liquid surface level control means sets the liquid surface height to the liquid contact height in a state where the base material is located at the coating start position and the coating nozzle is close to the base material. A relatively small amount of the coating liquid is supplied to the coating nozzle while being relatively increased to the above value to promote the liquid contact with the surface to be coated of the base material.

In the fifth aspect, the liquid level control means maintains the liquid level at the coating height set value while the coating liquid is being applied to the surface to be coated of the base material.

According to a sixth aspect of the present invention, the liquid surface control means lowers the liquid surface height relatively to the liquid separation height set value when the base material is located at the coating end position, so that the base material is coated. Suction the coating liquid that is in contact with the work surface to promote the syneresis.

According to the seventh aspect, the coating liquid replenishing means always fills the coating tank with the same amount of the coating liquid.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A coating apparatus 10 according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

The coating apparatus 10 of the present embodiment has a base material W of a plate material.
The coating liquid is applied to. For example, it is for forming an antireflection layer or a protective film on a glass plate used for a liquid crystal cell of a liquid crystal display device, and the coating thickness thereof is 0.01 μm to 5 μm. It should be noted that this is an example, and not limited to the glass plate of the liquid crystal cell, any plate-shaped substrate can be applied, and the type of the coating liquid is not limited.

(Structure of Coating Apparatus) FIG. 1 shows a coating apparatus 10
It is a block diagram of.

The plate-like base material W such as a glass plate is supported by a suction table having a suction port on its lower surface in a sucked state.
Can be moved in the front-rear direction (right side to left side in FIG. 1) by a motor 13.

Below the suction table 12, a coating nozzle 14 for coating the coating liquid on the lower surface of the base material W is arranged. The coating nozzle 14 has a beak-like top, and has a capillary gap 16 along the left-right direction.
Is provided, and the upper end of the capillary gap 16 serves as a discharge port 18 for the coating liquid. A liquid reservoir 19 is provided at the lower end of the capillary gap 16 as a space for evenly distributing the supplied coating liquid in the left-right direction.

The coating nozzle 14 can be moved up and down by an up-and-down moving device 20 composed of an air cylinder or a motor arranged below the coating nozzle 14 (from a dotted line state to a solid line state in FIG. 1).

A coating tank 22 for supplying a coating liquid is provided outside the coating nozzle 14. That is, the screw rod 26 is rotatably arranged in the vertical direction on the support portion 24 fixed to the wall of the coating nozzle 14.
A rack 28 is provided at the position 6. The coating tank 22 described above is attached to the rack 28. Screw rod 2
6 is rotatable by a motor 30 with a speed reducer,
When the motor 30 is rotated, the screw rod 26 rotates, and the rack 28, that is, the coating tank 22 moves up and down with respect to the coating nozzle 14. Further, since the support portion 24 is fixed to the coating nozzle 14, when the coating nozzle 14 moves up and down by the vertical movement device 20, the coating tank 2 is also moved.
2 also moves up and down.

The coating liquid is stored in the coating tank 22. The coating liquid is stored in the coating tank 22.

From the bottom of the coating tank 22, the coating nozzle 1
4 is provided with a supply pipe 34 for supplying the coating liquid toward the side surface. The coating liquid supplied from the supply pipe 34 reaches the liquid reservoir 19.

A non-contact type (for example,
An optical type liquid level sensor 32 is projected. The liquid level sensor 32 detects the liquid level of the coating liquid accumulated in the coating tank 22.

A replenishment tank 36 for supplying the coating liquid to the coating tank 22 is provided. This replenishment tank 36
A replenishment pipe 38 extends from the top of the coating tank 22. The replenishment pipe 38 is provided with a filter (not shown) and a solenoid valve 39. In addition, the replenishment tank 36
Is a closed type, and the coating liquid is supplied to the replenishment pipe 38 by an inert gas (for example, an inert gas or a nitrogen gas (N ₂ )) sent from a pressure feeding device 40 such as a compressor. Then, by operating the solenoid valve 39, a fixed amount of coating liquid is supplied to the coating tank 22. Here, the inert gas is sent for explosion protection, but if the purpose is not explosion protection, other gas such as air may be used.

A control unit 42 including a microcomputer is provided to control the coating apparatus 10.
The control unit 42 includes a motor 13 for moving the suction table 12, a vertical movement device 20, a motor 30 for vertically moving the coating tank 22, a liquid level sensor 32, a solenoid valve 39,
The pressure feeding device 40 is connected.

The control unit 42 detects the liquid level of the coating liquid by the liquid level sensor 32, drives the motor 30 based on the detected data to move the coating tank 22 up and down, and Feedback control is performed so that the liquid level in the coating tank 22 becomes a predetermined set value described below.

Further, the coating liquid is reduced by the coating,
When the liquid level height detected by the liquid level sensor 32 becomes lower than the reference value, the control unit 42 activates the pressure feeding device 40 to apply pressure with inert gas, and from the refill tank 36 via the refill pipe 38. The coating liquid is fed and a predetermined amount is replenished by operating the solenoid valve 39, and the coating liquid having a reference value or more is always stored in the coating tank 22.
As a result, the coating liquid that is conventionally discarded can be minimized.

(Coating Method) A first coating method for coating the lower surface of the substrate W with the coating apparatus 10 having the above-mentioned structure will be described with reference to FIGS. 2 (1) to 2 (4). I will explain in order.

(1) First step (see FIG. 2A) In the initial state, the substrate W is sucked by the suction table 12 and the coating nozzle 14 is in a standby state below it.

(2) Second step (see FIG. 2 (2)) The suction table 12 is moved by the motor 13 to stop the substrate W at the coating start position.

Further, the coating nozzle 14 is raised by the vertical movement device 20, and the ejection port 18 is stopped near the lower surface of the substrate W at the coating start position.

In this case, the coating tank 22 rises together with the coating nozzle 14, but not only the amount of the rise but also the liquid level of the coating liquid stored in the coating tank 22 using the motor 30. The height is set to the position of the upper end portion (that is, the discharge port) in the capillary gap 16 of the coating nozzle 14. In this setting, as shown in FIG. 1, it is considered that the liquid height of the capillary gap 16 is higher than the liquid height stored in the coating tank 22 by h1. The reason why there is a difference in height of h1 is that the coating liquid rises up to the upper end of the coating nozzle 14 in the capillary gap 16 due to the capillary phenomenon. Hereinafter, the liquid level height in the coating tank 22 will be referred to as a standby height set value.

(3) Third step (see FIG. 2C) The coating tank 22 is raised by the motor 30 with respect to the coating nozzle 14 while being detected by the liquid level sensor 32, and the liquid in the coating tank 22 is removed. The surface height is made higher than the standby height set value, and the coating liquid comes into contact with the lower surface of the base material W from the discharge port 18. Hereinafter, the liquid level height in the coating tank 22 will be referred to as a liquid contact height set value.

By this, the liquid contact can be performed quickly and surely.

In order to bring the liquid into contact with the liquid more reliably, the height of the coating nozzle 14 may be slightly raised by the vertical movement device 20.

(4) Fourth step (see FIG. 2 (4)) The height of the coating tank 22 is finely adjusted by the motor 30 while the coating liquid is in contact with the lower surface of the base material W. The liquid level in the coating tank 22 is set so that the target coating thickness is obtained (hereinafter, this height is referred to as a coating height setting value). Then, while the coating height set value is being detected by the liquid level sensor 32 and maintained by feedback control, the suction table 12 is started to be coated by the motor 13 while the coating liquid is being coated on the lower surface of the base material W. Move from the position to the coating end position.

As a result, the coating liquid is applied to the lower surface of the base material W.

(5) Fifth step (see FIG. 2 (2)) When the coating of the base material W is completed, the height of the coating tank 22 is detected by the motor 3 while being detected by the liquid level sensor 32.
0 to lower the liquid level in the coating tank 22 to the set liquid separation height and suck the coating liquid from the discharge port 18 to remove the coating liquid from the lower surface of the base material W. Let the liquid separate. This liquid separation height set value is lower than the liquid contact height set value and the coating height set value, and may be the same as the standby height set value.

As a result, the coating can be finished at the target position, and the width of the unstable region of the film thickness can be narrowed.

In this case, the coating nozzle 14 may be slightly lowered to further promote the syneresis.

By controlling the liquid level in the coating tank 22 as described above, the region where the film thickness is unstable at the beginning and the end of coating can be narrowed to ensure reliable coating. it can.

(Second Embodiment) A coating apparatus 10 of the second embodiment will be described with reference to FIG.

The difference between this embodiment and the first embodiment is the shape of the substrate W to be coated. That is, although the plate-shaped base material W is used in the first embodiment, in the present embodiment, the long base material W such as a film is coated.

For this purpose, a backup roll 50 is arranged above the coating nozzle 14 and a long base material is stretched over the backup roll 50.

The coating method is the same as in the first embodiment.

[0058]

As described above, according to the present invention, the coating liquid can be applied to the lower surface of the substrate by utilizing the capillarity only with the coating nozzle, so that the coating liquid is wasted. And the coating nozzle does not get dirty. Furthermore, the required coating thickness can be obtained quickly and reliably.

[Brief description of drawings]

FIG. 1 is an explanatory view of a coating apparatus showing a first embodiment of the present invention.

2 (1) to (4) are drawings showing a coating process of a coating apparatus.

FIG. 3 is an explanatory diagram of a coating device according to a second embodiment.

[Explanation of symbols]

10 Coating equipment 12 suction table 14 Coating nozzle 16 capillary gap 18 outlets 22 Coating tank 32 Liquid level sensor 34 Supply pipe

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Claims (9)

[Claims] 1. A coating nozzle having a capillary gap, the upper end of which serves as a discharge port for the coating liquid and which extends in the left-right direction, and a bear which is open to the atmosphere to store the coating liquid, and the coating liquid. A coating liquid supply unit that is in communication with the coating nozzle and can supply the coating liquid to the coating nozzle, and in a state where the coating nozzle is brought close to the substrate to be coated, along the discharge port. A moving means for moving the surface to be coated of the base material relatively in the front-rear direction, and the coating liquid supplying means while relatively moving the base material and the coating nozzle by the moving means. A coating apparatus which coats the coating liquid supplied to the coating nozzle from the discharge port of the coating nozzle onto the surface to be coated of the base material by a capillary phenomenon. 2. A coating tank, wherein the coating solution supply means stores the coating solution in a state of being opened to the atmosphere, and a coating tank for vertically moving the coating tank relative to the coating nozzle. The coating apparatus according to claim 1, further comprising: a tank vertical movement unit; and a liquid level detection unit that detects a liquid level height in the coating tank in a non-contact manner. 3. A liquid level control means for controlling the liquid level height detected by the liquid level detection means to a value arbitrarily set by using the coating tank vertical movement means. Item 2. The coating apparatus according to item 2. 4. The liquid level control means sets the liquid level to the liquid contact height in a state where the base material is located at a coating start position and the coating nozzle is close to the base material. The coating amount according to claim 3, wherein a small amount of the coating liquid is supplied to the coating nozzle while being relatively increased to a preset value to promote the liquid contact with the surface to be coated of the base material. Engineering equipment. 5. The liquid level control means maintains the liquid level at a coating height set value while the coating liquid is being applied to the surface to be coated of the base material. The coating device according to claim 3. 6. The liquid level control means, when the base material is located at a coating end position, relatively lowers the liquid level height to a set liquid separation height setting value, so as to cover the base material. The coating apparatus according to claim 3, wherein the coating solution which is in contact with the coating surface is sucked to promote the syneresis. 7. A coating liquid replenishing means for replenishing a coating liquid amount reduced from the coating tank, wherein the coating tank is always filled with the same coating liquid amount. The coating apparatus according to 2 to 6. 8. The base material is an elongated base material, and a backup roll for transporting the base material in the front-rear direction is arranged above the coating nozzle.
7. The coating apparatus according to 7. 9. The substrate is a plate-shaped substrate, and a suction table for adsorbing the plate-shaped substrate on its lower surface and conveying it in the front-rear direction is arranged above the coating nozzle. The coating device according to claim 1, which is characterized in that.