JP2010162486A - Slit nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slit nozzle for a spinless coater which monitors, without personal confirmation, whether the leading edge of a slit die is surely dipped in the surface of a washing liquid in a dipping tank in a drying prevention mode, and which controls the generation of foreign matters. <P>SOLUTION: In the slit nozzle for the spinless coater for applying a coating liquid on the surface of a sheet-like material to be treated with a constant width, an liquid level sensor to detect the liquid level of the dipping tank (a reservoir of the washing liquid) by dipping and holding the leading edge of the slit nozzle in the washing liquid in order not to dry, when the slit nozzle is not operated for constant hours or more during practising a series of application operations, is installed on at least one outer surface of both ends of the slit nozzle having an opening with a constant width. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a slit nozzle for a spinless coater for applying a coating liquid such as a resist to a surface of a plate-like workpiece such as a glass substrate with a certain width.

  Conventionally, there is a spin coating method as a coating method for coating a coating liquid such as a resist on the surface of a plate-like workpiece such as a glass substrate. This is because the coating liquid is dropped from the nozzle or slit to the center of the surface of the workpiece placed on the spinner, the workpiece is rotated by the spinner, and the coating liquid is diffused outward by the centrifugal force. It is a method of trying to apply | coat uniformly. In this case, the film thickness of the coating solution is controlled by the number of rotations and time. However, in this method, a little coating solution remains on the surface of the object to be processed, and most of the coating solution is scattered, which is wasteful.

  Therefore, instead of the spin coating method, a coating liquid discharge port slit having a predetermined width is opened in the nozzle itself, and the slit nozzle is moved at a constant speed, whereby the coating liquid can be uniformly applied to the surface of the object to be processed. It has been proposed as an efficient method that eliminates waste of the coating liquid. This is called a slit nozzle (die) coating method, and is often used for application of a photosensitive resin to a color filter substrate for a large liquid crystal display device.

  In this coating method, a coating solution is extruded from a slit of a die, moved at a constant speed, and coated while forming beads on a workpiece such as a glass substrate. In general, this slit die is formed by combining two or more blocks sandwiched from both sides by a side plate to form a slit, and once a supply port for supplying a coating liquid and the supplied coating liquid are fastened. It has a manifold portion for storing and spreading in the width direction and flowing uniformly in the longitudinal direction, and a slit for allowing the coating liquid to flow uniformly from the manifold in the width direction and discharging from the lip.

  However, it is necessary for the bead formation that the lip tip surface of the slit nozzle has good wettability with respect to the coating solution, but the lip tip side surface and the side plate tip part, which are usually made of the same material, also have good wettability with respect to the coating solution. Thus, the coating liquid spreads wet on the top surface of the side plate tip at both ends of the lip. The coating resist solution such as photosensitive resin adhering to the tip of the slit nozzle becomes a source of so-called regicus foreign matter by solidifying or drying, and also causes coating defects such as streaks and unevenness in the flow direction. There is. For this reason, as disclosed in Patent Document 1, it is necessary to remove the coating liquid at the nozzle tip and its peripheral portion by washing after coating. In addition, when the slit nozzle is not used for a certain period of time or periodically, it is essential to prevent the drying by immersing and holding the lip portion at the tip of the slit nozzle in the dip tank of the cleaning liquid.

  Usually, the cleaning liquid in the dip tank is periodically supplied to the dip tank by pressurization or the like, and the liquid level is kept constant by overflowing above a certain liquid level. However, if the flow rate of the supply liquid decreases due to, for example, a decrease in supply pressure or clogging of the supply pipe, the liquid level of the cleaning liquid decreases and the slit nozzle tip is not immersed in the cleaning liquid. Cause. Whether or not the lip portion at the tip of the slit nozzle is immersed in the surface of the cleaning liquid has to be dealt with by a method in which a person regularly checks visually with current equipment.

JP 2005-270848 A

  Slit nozzles (dies) equipped with a cleaning unit are usually made of glass, etc. for the sake of safety to maintain cleanliness of the environment, suppress scattering of organic solvent vapor and avoid contact with moving slit dies. It operates and operates in a clean booth surrounded by a partition wall with a door made of transparent plates. When a person checks whether the lip part at the tip of the slit die is immersed in the liquid level of the cleaning liquid in the dip tank, it will be checked over the glass plate, but it cannot be accurately confirmed due to light reflection, etc. When checking by opening the door, for safety, the coater unit must be temporarily stopped, which is not preferable in terms of maintaining cleanliness. The object of the present invention is to monitor whether or not the lip portion at the tip of the slit die is reliably immersed in the liquid level of the cleaning liquid in the dip tank in the dry prevention mode, and can be monitored without human confirmation, and the slit nozzle that suppresses the generation of foreign matter Is to provide.

  According to a first aspect of the present invention, there is provided a slit nozzle for a spinless coater for applying a coating liquid to a surface of a plate-like workpiece at a certain width. When not in use, a liquid level sensor for detecting the liquid level of the dip tank (cleaning liquid reservoir) that immerses and holds the tip of the slit nozzle in the cleaning liquid to prevent drying is provided at both ends of the slit nozzle having openings of a certain width. A slit nozzle is provided on at least one outer surface.

  The slit nozzle of the present invention has an opening of a certain width, and a liquid level sensor for detecting the liquid level of the dip tank is provided on at least one outer surface of both ends thereof. Therefore, in the step of applying a coating solution such as a photosensitive resin solution on the surface of a plate-like non-treated product such as a glass substrate, the tip of the slit nozzle is immersed in the cleaning solution of the dip tank when the slit nozzle is not used for a certain period of time. In the dry prevention mode, it is possible to always monitor whether the tip of the slit nozzle is surely immersed in the cleaning liquid of the dip tank, and it is possible to promptly deal with troubles such as a drop in the liquid level of the dip tank. As a result, it is possible to prevent the coating resist adhering to the tip of the slit nozzle from being dried, so that the so-called Regis foreign matter can be prevented, and the product defect rate can be reduced and the coating apparatus operating rate can be improved.

It is the schematic which illustrates the state where the front-end | tip is immersed in the washing | cleaning liquid of a dip tank by the example which has provided the liquid level sensor in the both-ends side surface of the slit nozzle which concerns on this invention. (A) of the slit die of an example of the slit nozzle which concerns on this invention is the schematic seen from the side surface, (b) is seen from the upper surface. It is the schematic of an example of the prior adjustment apparatus which consists of the cleaning apparatus of the front-end | tip of the slit nozzle which concerns on this invention, a drying prevention apparatus, and a preliminary discharge apparatus.

  Below, the slit nozzle of the present invention is explained based on one embodiment.

As shown in FIG. 1, the slit nozzle 10 of the present invention detects the level of the cleaning liquid 3 in the dip tank 2 by the liquid level sensor 1 provided on the outer side. Therefore, it is always monitored whether or not the tip of the slit nozzle is surely immersed in the cleaning solution of the dip tank in the drying prevention mode in which the tip of the slit nozzle is immersed in the cleaning liquid of the dip tank. When the tip of the slit nozzle is not immersed in the liquid level of the dip tank, an alarm is issued to prevent foreign matter from occurring.

  First, as shown in FIG. 2, the slit nozzle 10 of the present invention forms a slit 4 by combining at least two blocks 6 and 7 sandwiched from both sides by at least side plates 8 and 9, and applies a coating (not shown). A supply port for supplying the liquid, a manifold 5 for once retaining and storing the supplied coating liquid, spreading it in the width direction and flowing it uniformly in the longitudinal direction, and causing the coating liquid to flow uniformly in the width direction from the manifold A slit 4 for discharging from the lip 40 is provided. The liquid level sensor 1 is provided on one or both of the outer surfaces of the side plates. It is not preferable to provide the slit nozzle on the front side or the rear side with respect to the width direction because it becomes an obstacle when the tip of the nozzle is cleaned by a cleaning device described later.

  Liquid level sensors include non-contact type sensors that detect the temperature difference between the vicinity of the liquid level and the atmosphere, those that detect the reflection of ultrasonic waves at the liquid level, and optical sensors. . Examples of the contact type include a capacitance type and a float type. Since the slit nozzle of the present invention is applied by moving the upper surface of an object to be processed such as a glass substrate, a non-contact type liquid level sensor that is free from the risk of the cleaning liquid adhering and dropping is preferable.

  In the slit nozzle 10 of the present invention, a coating liquid supplied from a pump (not shown) passes through the manifold 5 and the slit 4, and then a bead is formed on the surface of the object to be processed such as a glass substrate at the lip 40, and the surface of the object to be processed is fixed. Apply while moving at speed. After the application is completed, the slit nozzle is carried to the cleaning adjustment device 100 illustrated in FIG. 3 to clean the tip of the nozzle and adjust the tip for the next coating.

  As described above, in the application with the slit nozzle, in order to form a stable bead, the lip portion at the tip of the nozzle needs to have a low contact angle with the coating liquid and good wettability. The coating resist solution such as photosensitive resin adhering to the tip of the slit nozzle becomes a source of so-called regicus foreign matter by solidifying or drying, and also causes coating defects such as streaks and unevenness in the flow direction. There is. Various measures have been taken to prevent the coating liquid from reaching the side of the tip of the lip, but the coating solution bead existing on the tip of the lip should not spread on the side of the slit nozzle. However, it is necessary to remove the coating liquid at the nozzle tip and its periphery by washing after application. In addition, when the slit nozzle is not used for a certain period of time or periodically, it is essential to prevent the drying by immersing and holding the lip portion at the tip of the slit nozzle in the dip tank of the cleaning liquid.

  The slit nozzle is carried to the cleaning device of the cleaning adjustment device 100 and cleans the nozzle tip by spraying a cleaning liquid. After cleaning the tip, it is carried to the dip tank 2 of the drying prevention device 20, and the nozzle tip is immersed in the cleaning liquid. At this time, it is detected by a liquid level sensor whether or not the nozzle tip is surely immersed in the cleaning liquid. When it is determined that it is not immersed, the cleaning liquid supply device 31 is notified and the cleaning liquid is supplied. When an object to be processed such as a glass substrate approaches the coating position, it is carried to a preliminary ejection device 50 that adjusts the slit nozzle for the next coating, and is applied to the preliminary ejection roll 51 to discard the coating liquid accumulated in the slit. After the preliminary discharge, the slit nozzle is moved to the application position and coating is performed.

  As described above, by using the slit nozzle of the present invention, troubles in resist coating of the color filter substrate used in the liquid crystal display device can be reduced, the defect rate can be reduced, and the coating device operating rate can be improved. Contributes to cost reduction.

DESCRIPTION OF SYMBOLS 1 ... Liquid level sensor 2 ... Dip tank 3 ... Cleaning liquid
4 ... Slit 5 ... Manifold 6,7 ... Block
8, 9 ... side plate 10 ... slit nozzle (slit die)
DESCRIPTION OF SYMBOLS 20 ... Drying prevention apparatus 30 ... Cleaning apparatus 31 ... Cleaning liquid supply apparatus 32 ... Cleaning liquid overflow 40 ... Lip part 41 ... Opening part 50 ... Preliminary discharge apparatus 51 ... Preliminary Discharge roll

Claims (1)

In a slit nozzle for a spinless coater for applying a coating liquid with a certain width on the surface of a plate-shaped workpiece,
Liquid level sensor that detects the liquid level in the dip tank (cleaning liquid reservoir) that prevents the slit nozzle from being dipped in the cleaning liquid and preventing drying when the slit nozzle is not used for a certain period of time during a series of coating operations. Is provided on at least one outer surface of both ends of the slit nozzle having openings of a certain width.

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