JP2006205031A - Slit die and coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slit die which is a slit die for forming a high precision coating film on a square glass substrate such as a color filter for a liquid crystal display and has a manifold formed by combining a plurality of metallic structures and having a fixed volume and a slit connected to the manifold, formed remarkably narrow and having narrow lips on both ends of the outlet part of the slit, has sufficiently adjustable width of the slit gap to be capale of correspond to the various coating liquids or various required thickness and is capable of being finely controlled and a coating apparatus on which the slit die is mounted. <P>SOLUTION: The slit die is equipped with a plurality of adjusting bolts A, adjusting bolts B and adjusting bolts C by which the gap of the slit in the short-side direction is controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slit die and a coating apparatus for forming a highly accurate coating film on a square glass substrate, such as a color filter for a liquid crystal display.

  One method for producing color filters used in liquid crystal displays and the like is a pigment dispersion method. In the coating process that plays the most important role in the pigment dispersion process, a die coating system using a highly accurate slit die is becoming the mainstream instead of the conventional spin coating system.

However, since the die coating method directly coats a thin film unlike the spin coating method, if the slit gap of the slit die is not uniform in the longitudinal direction, a difference occurs in the discharge amount of the coating liquid, and the coating film thickness becomes uneven. It has become a big problem that the vertical stripes become uneven.

  As a solution to the above problem, there is a method of adjusting the slit gap by providing an adjustment bolt such that the angle formed with the member to be coated is within a range of 20 ° before and after the traveling direction centering on 90 ° (for example, patent) Reference 1). In addition, there is a method of adjusting the slit gap by elastically deforming the slit die with a hydraulic unit (see Non-Patent Document 1, for example). However, in recent years, the adjustment amount of the slit gap is adjusted to be as large as possible within the elastic deformation range, and to a minute / narrow range in order to cope with diversification of coating liquid types, required coating film thickness, and higher quality. There is a need. Also, as the coating substrate becomes larger, the coating width of the slit die increases, so it is essential to reduce the size of the main body and reduce the weight.

  According to the method of Patent Document 1, in order to increase the adjustment amount of the slit gap, it is conceivable to reduce the thickness of the fulcrum portion of the elastic deformation. The rigidity of itself will also become low. Furthermore, if the adjustment bolt head faces the bottom side of the slit die, the adjustment itself can be easily performed. However, since the space of the adjustment bolt occupying the size of the adjustment bolt side block increases, the mechanism described in Patent Document 1 is used. There was a problem that it was difficult to incorporate it newly.

According to the method of Non-Patent Document 1, fine adjustment of the slit gap is possible, but it is difficult to increase the adjustment amount, as in the method of Patent Document 1. Further, since it is necessary to secure a space for the hydraulic unit itself, the slit die itself becomes large, and the mechanism is large and the initial cost increases. Furthermore, in the longitudinal direction of the slit die, it is suitable for a wide range of adjustment, but is not suitable for a narrow range of adjustment. The known literature is shown below.
JP H09-131561 A Convertec June 2004 Vol. 375, P.I. 60-P. 62, Published by Processing Technology Study Group

  The present invention solves the problems of the prior art, and the problem is that a combination of a plurality of metal structures and a manifold having a constant volume and an extremely narrow width connected to the manifold. Various types of coating in a slit die characterized by forming slits and having narrow lips on both sides of the exit of the slit, and having a path for supplying liquid from the outside and a path for discharging air The adjustment amount of the slit gap is sufficiently large so that it can correspond to the liquid and required film thickness, and it is possible to finely adjust the narrow range, and the adjustment itself can be performed easily, inexpensively, and the entire slit die An object of the present invention is to provide a slit die that can form a high-quality coating film with good film thickness uniformity without increasing the thickness, and a coating apparatus equipped with the slit die.

That is, in order to achieve the above object, according to the first aspect of the present invention, a plurality of metal structures are combined to form a manifold having a certain volume and a very narrow slit connected to the manifold. A slit die having a narrow lip on both sides of the outlet portion of the slit, and a path for supplying liquid from the outside to the manifold and a path for discharging air from the manifold to the outside. A plurality of adjustment bolts A capable of adjusting the gaps in the short direction of the slits arranged along the longitudinal direction are provided. The head of the adjustment bolt A is the slit die tip side, the tip of the adjustment bolt A Part faces the bottom side of the slit die, and the center line of the adjusting bolt A is perpendicular to the lip surface, and the head of the adjusting bolt is in the short direction of the slit die. It is inclined in the direction away from the lit, and the angle between the center line X of the adjusting bolt A and the direction Y perpendicular to the flat surface of the lip is in the range of 15 ° to 30 °. And a slit die.

Further, in the invention of claim 2, a plurality of adjustment bolts B capable of adjusting a gap in the short direction of the slit arranged along the slit die longitudinal direction from the adjustment bolt A toward the bottom surface of the slit die. A plurality of adjustment bolts C that can adjust the gap in the short direction of the slits arranged along the slit die longitudinal direction from the bolt B to the slit die bottom side, and the slit die length from the adjustment bolt C to the slit die bottom side. The slit die according to claim 1, wherein a plurality of fixing bolts arranged along the direction are provided in this order toward the bottom surface side of the slit die.

According to a third aspect of the present invention, there is provided a coating apparatus having the slit die according to the first or second aspect mounted thereon.

As described above in detail, according to the slit die and the coating apparatus according to the present invention, the following effects can be obtained. That is, by combining a plurality of metal structures, a manifold having a certain volume and an extremely narrow slit connected to the manifold are formed, and a narrow lip is provided on both sides of the exit portion of the slit, In addition, the slit die is characterized by having a path for supplying liquid from the outside and a path for discharging air, and the adjustment amount of the slit gap is large and the narrow range in the longitudinal direction of the slit die can be finely adjusted. It was possible to produce a high quality coated substrate with good film thickness uniformity. In addition, since the large-scale mechanism is not mounted, the size of the slit die itself can be suppressed, and it can be manufactured at a low cost. Furthermore, it is possible to easily adjust the slit interval by providing the adjusting bolt A with an inclination and mounting the adjusting bolt B and the adjusting bolt C on the same block. That is, the slit die and the coating apparatus intended by the present invention could be provided.

1 shows an embodiment of the invention. The present invention relates to a coating apparatus using a slit die for forming a highly accurate coating film on a square glass substrate, such as a color filter for a liquid crystal display, and as shown in FIG. (1) mainly comprises a manifold side block (2) and an adjustment bolt side block (3). Inside the slit die (1), there are a manifold (4) for temporarily storing the coating liquid, and a slit with a very small gap that is connected to the manifold and discharges the coating liquid inside the manifold to the outside ( 5) is formed. At the slit end on the discharge side of the coating liquid, a lip (8) is formed on both sides of the manifold side block (2) and the adjustment bolt side block (3) with a narrow, narrow and highly precise plane in the longitudinal direction of the slit die. ) Is formed.
The coating liquid tank (16) is pressurized by compressed clean air (11) by opening the coating liquid tank pressurization valve (12). The pressure of the compressed clean air (11) is adjusted by a pressure reducing valve (13) and a pressure gauge (14), and a filter (15) for collecting foreign matter between the pressure gauge (14) and the coating liquid tank (16). ) Is provided.

In order to supply the coating liquid (17) to the slit die (1), first, the coating liquid suction valve (18) is opened and the pump (20) is operated to receive the support of compressed clean air pressurization. Is sucked into the pump (20). Next, the coating liquid suction valve (18) is closed, the coating liquid supply valve (21) is opened, and the pump (20) is operated to supply the coating liquid to the manifold (4) through the supply port (6). . Between the coating liquid suction valve (18) and the pump (20), a primary filter (19) for collecting foreign matter is disposed between the coating liquid supply valve (21) and the slit die (1). A secondary filter (22) is provided.

Depending on the type of coating liquid, it is possible to suck the coating liquid from the coating liquid tank into the pump only by operating the pump (20) without pressurizing the coating liquid tank (16) with compressed air. The air accumulated in the manifold (4) opens the coating liquid supply valve (21) and the air vent valve (23) and operates the pump (20) to discharge it to the waste liquid tank (24) through the discharge port (7). Is done. As shown in FIG. 2, the slit die (1) of the present invention is fixed by a fixing bolt (31) in a state where the manifold side block (2) and the adjustment bolt side block (3) are bonded together. The adjustment bolt side block (3) is provided with a plurality of adjustment bolts A (38), adjustment bolts B (37), and adjustment bolts C (34) along the longitudinal direction.

  Adjustment bolt B (37) is fixed to slit die bottom side (32) from adjustment bolt A (38), and adjustment bolt C (34) is fixed to slit die bottom side (32) further than adjustment bolt B (37). The bolt (31) is further arranged on the slit die bottom side (32) than the adjusting bolt C (34). As shown in FIG. 3, the adjusting bolt A (38) is a differential screw, and is composed of a screw bush (61) and a set screw (62). There is a slight difference between the screw pitch of the screw bush (61) and the screw pitch of the set screw (62). When the screw bush (61) is rotated, a force is applied to the hinge portion (39) by the pitch difference, and the elastic deformation fulcrum. The adjustment bolt side block (3) is elastically deformed with the portion (40) as a fulcrum. That is, when the pitch of the screw bush (61) is wider than the pitch of the set screw (62), when the screw bush (61) is turned clockwise, the hinge portion (39) is pushed toward the slit die tip side (33). Thus, the elastic deformation fulcrum part (40) serves as a fulcrum, and the slit gap narrows. Conversely, when the screw bush (61) is turned counterclockwise, the hinge portion (39) is pushed to the bottom side (32) of the slit die, the elastic deformation fulcrum portion (40) serves as a fulcrum, and the slit gap is spread. If the pitch of the screw bush (61) is narrower than the pitch of the set screw (62), turning the screw bush (61) clockwise widens the slit gap and turns the screw bush (61) counterclockwise. And the slit gap narrows.

  Further, when the thickness h of the elastic deformation fulcrum (40) at the time of adjustment is increased, the amount of change in the slit gap with respect to the rotation angle of the screw bush (61) is reduced, and conversely, if h is reduced, the screw bush (61) The amount of change in the slit gap with respect to the rotation angle increases. Therefore, in order to finely adjust the slit gap, it is desirable to set the thickness h of the elastic deformation fulcrum part (40) to be thick.

  The head of the screw bush (61) of the adjustment bolt A (38) faces the slit die tip side (33), and the tip of the set screw (62) of the adjustment bolt A (38) faces the slit die bottom side (32). The center line X of the adjustment bolt A (38) is in the direction in which the head of the screw bush (61) moves away from the slit in the slit die short direction with respect to the direction Y perpendicular to the flat surface of the lip (8). Inclined. Furthermore, a mark is attached to the head of the screw bush (61) in order to grasp the rotation angle at the time of adjustment. In addition, since the flat surface of the lip (8) faces directly below during normal application standby and substrate application, it is easy to visually recognize the rotation angle during adjustment by slightly tilting the adjustment bolt A (38) itself.

  When the inclination angle θ between the direction Y perpendicular to the flat surface of the lip (8) and the center line of the adjusting bolt A is smaller than 15 °, it is difficult to confirm the rotation angle when viewed from the horizontal plane. When the angle is larger than 30 °, the amount of change in the slit gap with respect to the rotation angle during adjustment becomes large, and it is necessary to increase the thickness of the adjustment bolt side block (3) structurally. Will become larger. In other words, the inclination angle θ needs to be in the range of 15 ° to 30 °, and the rotation angle is easier to see and the size of the slit die is more in the range of 21 ° to 25 °. This is preferable because the thickness can be suppressed and fine adjustment is possible.

  The adjustment bolt B (37) is a hexagon socket head bolt, and when the adjustment bolt B (37) is tightened, the slit gap is narrowed. At this time, by controlling the tightening force of the adjusting bolt B (37) with a torque wrench, it is possible to adjust the amount by which the slit gap narrows. The adjusting bolt C (34) is a hexagon socket set screw and is used as a push bolt. The adjusting bolt C (34) is fixed by tightening the fixing push bolt (35). When the adjustment bolt C (34) is tightened, the counterbore hole (36) is pushed, so that the slit gap widens. At this time, by controlling the tightening force of the adjusting bolt C (34) with a torque wrench, it is possible to adjust the amount of expansion of the slit gap.

  Since these adjusting bolts B (37) and C (34) directly push and pull the manifold side block (2), it is possible to adjust a sufficiently wide slit gap. Also, the adjustment bolt A (38), the adjustment bolt B (37), and the adjustment bolt C (34) are all provided on the adjustment bolt side block (3), so that the adjustment itself can be easily performed. It is.

  Furthermore, since the structure itself is not a special thing and a relatively simple mechanism using only the adjusting bolt is used, the initial cost at the time of manufacture can be kept low. Furthermore, the adjusting bolt A (38) deforms the adjusting bolt side block (3) to adjust the slit gap, and the adjusting bolt B (37) and the adjusting bolt C (34) deform the manifold side block (2). Since the slit gap is adjusted, the stress when a force is applied is not concentrated on the block on one side, and the burden on the slit die body can be reduced even during adjustment involving a large deformation.

  As shown in FIGS. 2 and 4, in the coating apparatus of the present invention, the slit die (1) is suspended by the top plate (41), moved up and down by the vertical precision driving device (42), and horizontally It is moved in the horizontal direction by a precision drive (43). In addition to the above unit, the coating apparatus is constituted by a precision table (44) for placing a glass substrate (51). In addition, the slit die itself may move in the horizontal direction to perform application, or the slit die may be fixed and the precision table may move to perform application. Moreover, the manifold (4) and the slit (5) can be formed by closing both ends of the slit die (1) with side plates (45).

A case where a photosensitive material is applied using a slit die in a manufacturing process of a color filter for a liquid crystal display will be described as a slit die and a coating apparatus of the present invention. A slit die having a slit gap of 100 μm and a slit length in the longitudinal direction of the slit die of 675 mm was used. 34 adjustment bolts A were arranged at regular intervals, 34 adjustment bolts B were arranged at 18 regular intervals, and 20 adjustment bolts C were arranged at regular intervals. In addition, these positions, the number, and the arrangement interval may be appropriately determined depending on the longitudinal length of the slit die, the position to be adjusted, and the like. The inclination angle of the center line of the adjusting bolt A was 21 °. Furthermore, the screw bushing of the adjusting bolt A was used with a larger pitch than the set screw.

  The photosensitive material to be applied was a commercially available negative resist, the glass substrate to be applied was non-alkali glass, and the size was 680 mm × 880 mm × 0.7 tmm. The target coating film thickness was 2.0 μm ± 1% (excluding 10 mm at both ends) in the longitudinal direction of the slit die.

The actual operation is shown in detail below.
As shown in FIGS. 1, 4 and 5, the glass substrate (51) is placed on the precision table (44) and vacuum-sucked by a transfer robot of a loader unit (not shown). The coating liquid tank pressurization valve (12) is opened in advance, and the coating liquid tank (17) is constantly pressurized. The slit die (1) is assembled in advance on a precision surface plate (not shown) and fixed to the top plate (41). At this time, the adjusting bolt A (38) of the slit die (1) has a rotation angle of 0 °, and the adjusting bolt B (37) and the adjusting bolt C (34) are all in a tightening torque of 0 Nm.

  In order to supply the negative resist into the slit die (1), the following operation is performed in advance. That is, by opening the coating liquid suction valve (18) and operating the pump (20), negative resist is sucked from the coating liquid tank (16), then the coating liquid suction valve (18) is closed, and the coating liquid supply valve (21 ) And the air vent valve (23) are opened, the pump (20) is operated, the coating liquid is supplied to the slit die (1), and the air accumulated in the manifold (4) is discharged to the waste liquid tank (24). . By repeating the above operation several times, the inside of the slit die (1) is completely filled with negative resist.

  The slit die (1) stands by at the application start upper position (S), and when the glass substrate (51) is placed on the precision table (44), the vertical precision driving device (42) is used. Lower to the application start position (T). In this state, the coating liquid supply valve (21) is opened to operate the pump (20) to form the coating bead (52), and then the coating is completed while forming the coating film (53) by the horizontal precision driving device (43). Translate to position (U). When the slit die (1) moves to the coating end position (U), the operation of the pump (20) is stopped, the coating liquid supply valve (21) is closed, and the discharge of the negative resist is stopped. Next, it moves up to the coating end upper position (V), then moves to the coating start upper position (S), and waits for the next glass substrate to be placed on the precision table (44).

  In preparation for the next application, the slit die starts to rise to the upper position (V) at the end of application. At the same time, the application liquid intake valve (18) is opened and the pump (20) is operated to suck the negative resist into the pump. When the suction is finished, the coating liquid suction valve (18) is closed. On the other hand, the glass substrate (51) coated with the negative resist is placed on a film thickness meter (not shown) by a transfer robot (not shown), and the coating film thickness in the longitudinal direction of the slit die (1) is measured in-line.

  At this time, the film thickness measurement result in the longitudinal direction of the slit die of the reference substrate applied in a state where the rotation angles of the adjustment bolt A are all 0 ° and the tightening torques of the adjustment bolt B and the adjustment bolt C are all 0 Nm is shown in FIG. The film thickness uniformity was about 2.0 μm ± 5%. From this result, the adjustment bolt C (34) in the portion having a low film thickness was tightened with a constant torque, and the adjustment bolt B (37) in a portion with a thick film thickness was further tightened with a constant torque, and coating was performed again. . As a result, the film thickness uniformity was about 2.0 μm ± 2%, but the film thickness uniformity could not be improved further. In this state, the adjustment bolt A (38) was finely adjusted so that the thick part was thin and the thin part was thick, and coating was performed again. As a result, the film thickness uniformity finally reached within 2.0 μm ± 1%, and the target value could be achieved.

It is explanatory drawing which shows the outline of the coating device using a slit die. It is sectional drawing of the longitudinal direction of the slit die of this invention. It is a cross-sectional enlarged view of the adjustment bolt A vicinity of the slit die of the present invention. It is the perspective view which showed an example of the coating device of this invention. It is explanatory drawing which represented typically the operation | movement of the coating device of this invention. It is the graph showing the film thickness distribution of the longitudinal direction of the slit die at the time of apply | coating with the slit die of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Slit die 2 ... Manifold side block 3 ... Adjustment bolt side block 4 ... Manifold 5 ... Slit 6 ... Supply port 7 ... Discharge port 8 ... Lip 11 ..Compressed clean air 12 ... application liquid tank pressurizing valve 13 ... pressure reducing valve 14 ... pressure gauge 15 ... filter 16 ... application liquid tank 17 ... application liquid 18 ... application liquid Suction valve 19 ... Primary filter 20 ... Pump 21 ... Application liquid supply valve 22 ... Secondary filter 23 ... Air vent valve 24 ... Waste liquid tank 31 ... Fixing bolt 32 ...・ Slit die bottom side 33 ... Slit die tip side 34 ... Adjustment bolt C
35 ... Fixing push bolt 36 ... Counterbore hole 37 ... Adjustment bolt B
38 ... Adjustment bolt A
39 ... Hinge 40 ... Elastic deformation fulcrum 41 ... Top plate 42 ... Vertical precision drive 43 ... Horizontal precision drive 44 ... Precision table 45 ... Side plate 51 ... Glass substrate 52 ... Application bead 53 ... Application film 61 ... Screw bush 62 ... Set screw S ... Application start upper position T ... Application start position U ... Application End position V ... Upper end position of application h ... Elastic deformation fulcrum wall thickness? ... Adjustment bolt A center line inclination angle X ... Adjustment bolt A center line Y ... Lip surface vertical direction

Claims (3)

  Combining a plurality of metal structures to form a manifold with a certain volume and a very narrow slit connected to the manifold, with narrow lips on both sides of the outlet of the slit, the exterior to the manifold It is possible to adjust the gap in the short direction of the slit arranged along the longitudinal direction of the slit die in the slit die characterized by having a path for supplying more liquid and a path for discharging air from the manifold to the outside. A plurality of adjustment bolts A, the head of the adjustment bolt A is directed to the slit die tip side, the tip of the adjustment bolt A is directed to the bottom side of the slit die, and the slit die short direction The head of the adjusting bolt is inclined in a direction away from the slit, and the center line X of the adjusting bolt A and the direction Y perpendicular to the flat surface of the lip are formed. A slit die degrees to being in the range of 15 ° to 30 °.   A plurality of adjustment bolts B that can adjust the gap in the short direction of the slits arranged along the slit die bottom direction from the adjustment bolt A to the slit die bottom side, and slits from the adjustment bolt B to the slit die bottom side. A plurality of adjustment bolts C capable of adjusting the gaps in the short direction of the slits arranged along the longitudinal direction of the die, and a plurality of arrangements arranged along the longitudinal direction of the slit die from the adjustment bolts C to the bottom side of the slit die. The slit die according to claim 1, wherein the fixing bolts are provided in this order toward the bottom surface side of the slit die.   A coating apparatus comprising the slit die according to claim 1 or 2 mounted thereon.

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