JP2007025334A - Spacer ink spraying device, and spacer ink spraying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a state of stopping a system as far as possible by detecting appropriateness of a sprayed state of a spacer ink on a substrate at an early stage and performing necessary repairing. <P>SOLUTION: In a liquid drops spraying stage 13, liquid drops of the spacer ink are sprayed on the substrate 1 with an inkjet means 23. A liquid drops detecting means 28 constructed with an image pickup means equipped with a camera and a flash is installed on the downstream side of the liquid drops spraying stage 13. When a dropout of the liquid drops is detected, after completion of spraying on the substrate 1, a transfer table 20 and a movable carriage 25 are driven so as to make an inkjet head 26 face a dropout position of the liquid drops on the substrate 1, and the spacer ink is ejected toward the dropout position, and subsequently clogging of a nozzle 30 is dissolved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a spacer made of fine particles as a display panel such as a liquid crystal panel, in order to form a gap constituting a cell gap that forms a liquid crystal sealing space between two transparent substrates that are superposed on each other. The present invention relates to an apparatus and a method for dispersing and fixing spacer ink droplets on a substrate surface.

  As a liquid crystal display device, for example, a color TFT liquid crystal panel is composed of a TFT substrate made of a transparent substrate such as glass and a color filter joined together, but the TFT substrate and the color filter are not in a close contact state, It is joined through a minute gap called a so-called cell gap, and liquid crystal is sealed in this gap. A minute gap forming the liquid crystal sealing space is secured by a spacer. The spacer is composed of spherical fine particles, and is generally dispersed on the TFT substrate side when configured as a liquid crystal panel.

  In order to make the gap serving as the cell gap uniform, it is necessary to uniformly disperse the fine particles constituting the spacer throughout the substrate. Moreover, the color filter side substrate bonded to the TFT substrate is provided with RGB color filters so as to correspond to the pixels of the TFT substrate, and a black matrix is formed between the pixels of each color. Since the spacers are opaque particles, the spacers are arranged in the black matrix area, avoiding the pixel areas where the filters of the respective colors are formed, in order to prevent image quality deterioration in the liquid crystal panel. For this purpose, it is necessary to control the dispersion position of the spacers and to make sure that they are directed to the black matrix region.

  In order to control the dispersion position of the spacers, for example, Japanese Patent Application Laid-Open No. 2003-260260 proposes an ink jet system as the dispersion means. Here, the spacer used in the ink jet has a particle diameter of about 5 μm or less, and preferably has a minute spherical shape of about 3 to 5 μm. The hole diameter of the ink jet nozzle used for this kind of application currently in practical use is about 30 μm. The spacer is dispersed uniformly in the ink containing the solvent, thereby forming a spacer ink. The spacer ink is ejected from the inkjet nozzle toward the substrate and is deposited as a droplet on the substrate. The mixing ratio of the ink and the spacer is set so that at least one spacer and at most about 4 to 5 spacers are included therein.

Then, for example, the substrate is set in a state where it is positioned on a table that is conveyed in a predetermined direction, that is, in the X direction, and the substrate is placed in the X direction with an inkjet head provided with a predetermined number of ejection nozzles facing the substrate. During the movement, the spacer ink can be dispersed over the entire surface of the substrate so as to scan in the direction perpendicular to the feed of the substrate, that is, in the Y direction.
JP 2003-279999 A

  By the way, the ink jet head in the ink jet means is provided with minute nozzles in order to eject the droplets of the spacer ink toward the substrate, and a plurality of these minute nozzles are arranged with a predetermined pitch interval. Since the spacer ink ejected from each of these micro nozzles is obtained by dispersing micro particles in the ink, the micro particles may cause clogging of the nozzle. If any of the predetermined number of micro nozzles provided in the ink jet head is clogged, the spacer ink droplets supplied to the substrate will be missing. The substrate on which such droplets have dropped out is a defective product, and it is necessary to wash out all the spacer ink from the substrate and spray the spacer ink again. Further, if the spraying of the spacer ink is continued while overlooking that some of the nozzles are clogged, defective products will be continuously generated.

  Therefore, it is necessary to detect whether or not the droplets are properly sprayed on the substrate. For this purpose, for example, after the spacer ink is sprayed, the surface of the substrate is photographed with a camera, By performing image processing, it is possible to detect dropout on the substrate. When the dropout of the droplet is detected, the nozzle clogging can be eliminated by cleaning the nozzle constituting the inkjet head. In addition, by quickly cleaning the substrate in which the dropout of the droplet is detected, the droplet and ink remaining on the substrate can be completely removed, and the substrate can be regenerated.

  However, even if a drop of spacer ink droplets on the substrate occurs, it may be possible to repair the drop by another nozzle in the inkjet head. In addition, if the nozzles are lightly clogged, the nozzles may be clogged by applying a high pressure to the nozzles and ejecting the spacer ink. As described above, if the dropout of the droplet is repaired or the nozzle clogging is eliminated, the operation of the system can be continued as it is.

  Therefore, an object of the present invention is to detect the dispersion state of the spacer ink at an early stage and perform necessary repairs so that the system can be prevented from stopping as much as possible.

  In order to achieve the above-described object, in the present invention, in order to form a panel bonded with a predetermined gap by interposing a spacer made of fine particles between two transparent substrates, a spacer made of fine particles is used. The configuration of the apparatus for spraying the spacer ink contained in the ink on the surface of one of the two transparent substrates is as follows. The substrate conveying means for conveying the substrate in a horizontal state, and the substrate conveying means. An inkjet unit that is mounted so as to reciprocate in a direction orthogonal to the transport direction of the substrate, and that has a predetermined number of nozzles for supplying droplets of the spacer ink to the surface of the substrate, and downstream of the inkjet unit A liquid that is disposed and moves in conjunction with the ink jet means to detect a droplet immediately after the spacer ink is supplied to the substrate surface. Based on a signal from the monitoring means and the droplet monitoring means, it is determined whether or not the droplets are properly distributed on the substrate. It is characterized by comprising an ink jet control means for operating the ink jet means in accordance with a repair procedure when it is determined whether or not repair is possible.

  Further, in order to form a panel bonded with a predetermined gap by interposing a spacer made of fine particles between two transparent substrates, a spacer ink containing a spacer made of fine particles in the ink is used as the transparent substrate. Among them, for the invention of the method of spraying on the surface of one substrate, while the substrate is transported in a horizontal state by the substrate transport means, while reciprocating the inkjet means in a direction perpendicular to the transport direction of the substrate, The spacer ink is supplied to the substrate surface and operates in conjunction with the ink jet means. Immediately after being supplied to the substrate by the ink jet means, the droplets of the spacer ink are properly dispersed on the substrate surface. Whether or not the droplets are sprayed onto the substrate is inappropriate. When recovery is possible, the actuates the ink jet unit, the or distribute modifications of the droplet is set to its features.

  In order to minimize the situation of system shutdown, it is most important to quickly detect when a nozzle in the inkjet means is clogged. The droplet monitoring means detects the droplet on the substrate immediately after ejecting the spacer ink from the ink jet means. While the substrate is being transported by the substrate transporting means, spacer ink ejected intermittently from each nozzle constituting the ink jet means adheres as droplets to the surface of the substrate. Accordingly, the droplet monitoring means is arranged on the downstream side of the ink jet means and is configured to move in synchronization with the ink jet means. As a result, detection can be performed immediately after droplet formation on the substrate.

  Droplet detection by the droplet monitoring means can be performed using a transmissive or reflective sensor, and a camera is used to detect not only the presence or absence of droplets but also their size. desirable. In order to detect droplets more accurately, a flash is used, and this flash is operated in conjunction with a shutter, and the substrate is photographed under the flash irradiation of the flash, thereby capturing the droplet more clearly. it can.

  When droplets are missing on the substrate, the spraying of the spacer ink is once completed on the entire surface of the substrate as it is, and the substrate transporting unit is operated to return the substrate to the position before the spraying. In this state, the other part of the ink jet head that constitutes the ink jet means is not clogged, and the part where the liquid droplets are removed is corrected. After this correction is completed, the nozzle clogging is released. This clogging can be released by ejecting spacer ink from the nozzle at high pressure and discarding it. In order to enable this disposal, it is desirable to provide a container for receiving the spacer ink.

  When the droplet correction on the substrate and the clogging of the nozzle are released, the operation can be continued as it is, and there is no need to stop the system. However, if it is impossible to correct the droplet using another nozzle, the substrate is excluded from the system. If the clogging of the nozzle cannot be removed, the system is stopped and the nozzle is cleaned.

  As a result, even when nozzle clogging occurs, it is possible to suppress the system from being stopped to the minimum, and the operation of spraying spacer ink onto the substrate can be performed efficiently.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, in FIG. 1, reference numeral 1 denotes a substrate, and this substrate 1 is a transparent substrate made of glass or the like, specifically, for example, a TFT substrate. Switching elements made of thin film transistors are formed in a matrix on the substrate 1, and the color filters are bonded in an aligned state. In the figure, reference numeral 2 denotes a pixel area constituting pixels of each color of RGB, and the pixel area 2 is partitioned by a black matrix area 3. When the spacers 4 are uniformly dispersed in the black matrix region 3 and the TFT substrate and the color filter are joined by the spacers 4, a gap called a cell gap is formed. Thus, a liquid crystal panel is formed by enclosing liquid crystal in the gap between the two substrates formed by the spacer 4.

  FIG. 2 shows the overall configuration of a system for dispersing and fixing spacers on the substrate 1. In the figure, 10 is a work carry-in part, and 11 is a work carry-out part. The substrate 1 to be processed is carried in from the work carry-in unit 10. Then, the substrate 1 carried in in this way is transferred to the droplet spraying stage 13 through a pretreatment stage 12 for performing a process such as surface modification, if necessary. In the droplet spraying stage 13, spacer ink is sprayed on the surface of the substrate 1.

  After the spacer ink is sprayed on the surface of the substrate 1, the substrate 1 moves to the first heat treatment stage 14 so as to volatilize the ink component from the spacer ink, so that only the spacer 4 remains on the substrate. . Next, in the second heat treatment stage 15, the substrate 1 is baked to fix the spacers to the substrate surface.

  Here, the substrate 1 is heat-treated in two stages. First, in the first stage, the spacer ink properly applied from the ink jet means 23 is dried to remove the ink components, and the spacer 4 remains on the substrate 1. In addition, when the substrate 1 is rapidly heated to a high temperature, the individual spacers in the spacer ink are dried in a disjointed position. The spacer is made of fine particles, and it is desirable that a plurality of spacers are gathered to some extent. For this purpose, the substrate 1 is heated at a low temperature and slowly dried, whereby the plurality of spacer particles are attracted and concentrated in the central direction of the liquid. Then, in the second stage, the substrate 1 is baked by heating it at a high temperature, and the spacer 4 having dried ink is fixed to the substrate 1.

  As shown in FIG. 3, the substrate 1 is placed on a transfer table 20 and is fixedly held on the transfer table 20 by means such as vacuum suction. The transport table 20 is transported along the X-axis guide 22 in the X direction in the figure by the ball screw feeding means 21. In the transport path in the X direction of the transport table 20, the droplet application stage 13 disposed on the downstream side of the surface modification stage 12 has the configuration shown in FIG. When the substrate 1 is carried into the droplet spraying stage 13, spacer ink is sprayed on the surface of the substrate 1.

  For this purpose, an ink jet means 23 is provided on the droplet spreading stage 13, and this ink jet means 23 is mounted on a Y-axis guide 24 having a gate shape so as to straddle the transport table 20. The shaft guide 24 is provided with a moving table 25 on which the ink jet means 23 is installed. The moving table 25 is movable in the Y direction orthogonal to the conveying direction of the conveying table 20. The ink jet unit 23 includes an ink jet head 26 and an ink bottle 27, and the ink jet head 26 and the ink bottle 27 are moved in the Y direction along the Y axis guide 24 by the moving base 25.

  Further, the moving table 25 is provided with a droplet detection means 28 at a position closest to the mounting position of the ink jet means 23 in the feed direction of the transport table 20 and downstream of the ink jet means 23. The droplet detection means 28 is an image pickup means including a camera and a flash, and the camera has a part of the area where the spacer ink droplets are formed as a visual field range. The droplet detecting means 28 scans in the Y direction together with the ink jet means 23 by the movement of the moving table 25, and an image for determining whether or not the spacer ink is properly dispersed on the substrate 1 during this time. Is acquired.

  As shown in FIG. 4, the ink jet head 26 constituting the ink jet means 23 is composed of a large number of minute nozzles 30 arranged at a predetermined pitch interval, and a constant amount of spacer ink is intermittently supplied from each minute nozzle 30. It can be sprayed on. The ejection of the spacer ink is individually controlled for each minute nozzle 30 to eject the spacer ink. As shown in FIG. 5, the inkjet head 26 includes a chamber piece 31 communicating with the minute nozzle 30, and the chamber piece 31 is connected to an ink supply path from the ink bottle 27.

  An actuator 32 made of a piezoelectric element is attached to the chamber piece 31. When a voltage is applied to the actuator 32, the actuator 32 is deformed and the chamber piece 31 expands as shown by a one-dot chain line in FIG. It will be. As a result, the spacer ink is sucked into the chamber piece 31 from the ink bottle 27 side. Next, when the application of voltage to the actuator 32 is interrupted, the original state is restored, the volume of the chamber piece 31 is reduced, and the corresponding spacer ink is ejected from the micro nozzle 30.

  Therefore, while the substrate 1 is intermittently sent in the X direction by the transport table 20, the spacer ink is ejected from each minute nozzle 30, whereby droplets of the spacer ink are dropped on the substrate 1. Further, the inkjet head 26 reaches only a part of the substrate 1 in the width direction, and for this reason, the inkjet head 26 scans in the Y direction. An ink jet control device 29 is provided to control the operation of the ink jet head 26 including the ejection control of the spacer ink by the micro nozzles 30.

  A control device 33 is connected to the droplet detection means 28 composed of an imaging means equipped with a camera and a flash, and the operation of the camera and the flash is controlled by this control device 33. That is, when the substrate 1 is transported by a predetermined amount by the transport table 20 and the movable table 25 is moved by a predetermined amount in the direction orthogonal thereto, the flash is activated, and in conjunction therewith, the camera 1 Department is filmed. An image acquired by this camera is taken into the control device 33, and it is determined whether or not a droplet exists at a predetermined position by image recognition.

  When it is determined that the droplets are formed at the proper position and in the normal size on the entire substrate 1, the inkjet head 26 is operating accurately, and the operation is continued as it is. Thus, the spraying of the spacer ink on the substrate 1 is continued successively. When any one of the minute nozzles 30 constituting the ink jet head 26 is clogged, no droplets are present in the corresponding row in the substrate 1 and dropout occurs or other droplets are generated. Smaller. In this case, since drop drop (or non-uniformity) is detected by the droplet monitoring means 28, based on the output signal from the control device 33, the droplet correction of the substrate 1 by the inkjet control device 29, The operation of releasing clogging of the nozzle 30 is performed. It should be noted that the correction of the droplet is a case where a dropout occurs, and the nonuniformity of the droplet size cannot be corrected.

  The correction of the dropout of the substrate 1 is not performed every time the dropout of the droplet is detected, but is corrected by adding the droplet after the spacer ink is once sprayed on the entire surface of the substrate 1. That is, the control device 33 stores the coordinate position of the dropout portion detected based on the image recognition, and drives the transport table 20 and the movable table 25 after the completion of the spraying of the substrate 1. The ink jet head 26 is brought into contact with the dropout portion of the substrate 1 and the spacer ink is ejected toward the dropout portion. Here, the inkjet head 26 includes a large number of minute nozzles 30, but the nozzles 30 for adding droplets are specified in advance. For example, the nozzles at either end of the inkjet head 26 can be specified for adding droplets. If the nozzle identified in this way is clogged, the nozzle at the next position is used for adding a droplet.

  When the inkjet head 26 is provided with only one row of nozzles 30, continuous omission occurs in the same row. On the other hand, when the nozzles 30 are provided in a plurality of rows, there are intermittent gaps. In any case, the ink jet head 26 is operated so as to replenish droplets in all missing portions. Since the replenished droplet has a time difference with other droplets already applied, the degree of ink drying differs. However, since the replenishment of the droplets is performed immediately after the spraying on the substrate 1, the time difference does not occur so much. Therefore, there is substantially no difference in the drying time, and the subsequent process, that is, the baking process in the second heating stage 15 is not affected.

  The fact that the droplets are missing means that any nozzle 30 constituting the inkjet head 26 is clogged. The clogging of the nozzle 30 can be identified from the dropout portion of the droplet. Therefore, after the spraying on the substrate 1 is finished, the clogging is canceled for the nozzle 30 in which the clogging has occurred. Since the main cause of the clogging of the nozzle 30 is the fine particles contained in the spacer ink, when a high pressure is applied to the chamber piece 31, the fine particles that are jammed in the narrow passages constituting the nozzle 30 are formed. It is discharged and the passage of the nozzle 30 is improved. For this purpose, a high voltage is applied to the actuator 32 made of a piezoelectric element so that the actuator 32 is quickly restored after being largely deformed. At this time, the spacer ink ejected from the nozzle 30 is discarded. In order to receive the discarded spacer ink, a container 34 for receiving the discarded spacer ink is provided in a movable range of the inkjet head 26 and at a position that does not interfere with the transport table 20.

  By operating as described above, most of the clogging in the nozzle 30 is released. However, there are cases where the clogging of the nozzle 30 is not eliminated even after the clogging is released. In this case, the system is stopped and the nozzle 30 is repaired. Of course, even in this case, since the dropout of droplets can be supplemented with the other nozzles 30 for the substrate 1 being sprayed, the system must be stopped during the spraying. Never do. In addition, the system stop does not have to be performed immediately after the nozzle 30 becomes clogged, but it is also possible to continue the spraying of the spacer ink to some extent by repairing the omission and stop the system at the timing. It becomes possible.

It is structure explanatory drawing of the board | substrate with which a spacer is spread | dispersed. It is explanatory drawing which shows the whole structure of the mechanism which spreads and fixes the spacer to a board | substrate. It is an external view which shows the structure of a droplet dispersion | distribution stage. It is a structure explanatory view showing the tip part of an ink jet head. It is explanatory drawing of the operation | movement which ejects the spacer ink from the micro nozzle which comprises an inkjet head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Pixel area 3 Black matrix area 4 Spacer 10 Work carry-in part 11 Work carry-out part 12 Surface modification stage 13 Droplet dispersion stage 14 First heat treatment stage 15 Second heat treatment stage 20 Transport table 23 Inkjet means 26 Inkjet head 27 Ink Bottle 28 Droplet Detection Means 29 Inkjet Control Device 30 Micro Nozzle 31 Chamber Piece 32 Actuator 33 Control Device 34 Container

Claims (4)

In order to form a panel bonded with a predetermined gap by interposing a spacer made of fine particles between two transparent substrates, a spacer ink containing a spacer made of fine particles in the ink is used for the two transparent substrates. A device for spreading on the surface of one of the substrates,
Substrate transport means for transporting the substrate in a horizontal state;
An inkjet unit that is mounted so as to reciprocate in a direction orthogonal to the substrate transport direction by the substrate transport unit, and includes a predetermined number of nozzles that supply droplets of the spacer ink to the surface of the substrate;
Droplet monitoring means that is disposed downstream of the ink jet means, moves in conjunction with the ink jet means, and detects a liquid drop immediately after the spacer ink is supplied to the substrate surface;
Based on the signal from the droplet monitoring means, it is detected whether or not the droplets are properly distributed on the substrate. A spacer ink spraying apparatus comprising: an ink jet control unit that operates the ink jet unit according to a repair procedure when it can be repaired. 2. The spacer ink spraying device according to claim 1, wherein the droplet monitoring means comprises a camera and a strobe for photographing the substrate surface. In order to form a panel bonded with a predetermined gap by interposing a spacer made of fine particles between two transparent substrates, a spacer ink containing a spacer made of fine particles in the ink is used in the transparent substrate. , A method of spraying on the surface of one substrate,
While the substrate is transported in a horizontal state by the substrate transport means, the ink jet means is reciprocated in a direction orthogonal to the transport direction of the substrate while supplying the spacer ink to the substrate surface,
Operates in conjunction with the ink jet means, and immediately after being supplied to the substrate by the ink jet means, detects whether or not the spacer ink droplets are properly dispersed on the substrate surface,
Spacer ink characterized in that droplets are not properly sprayed onto the substrate but can be repaired by the operation of the ink jet means, and the ink jet means is actuated to correct the dispersion of the liquid droplets. Spraying method. When improper dispersion of droplets on the substrate is a dropout of droplets due to clogging of the nozzles constituting the ink jet means, the repair is performed using other nozzles constituting the ink jet means. The spacer ink spraying method according to claim 3.

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