JP5384816B2 - Droplet coating apparatus and droplet coating method - Google Patents

Description

  The present invention relates to a droplet applying apparatus and a droplet applying method for applying droplets by applying droplets to an object to be applied.

  When manufacturing a display device such as a liquid crystal display device, an organic EL (Electro Luminescence) display device, an electron emission display device, a plasma display device, or a semiconductor device, for example, when forming a color filter (for example, Patent Document 1), or when a functional thin film such as an alignment film or a resist is formed on a substrate such as a glass substrate or a semiconductor wafer.

  This droplet coating apparatus includes a coating head that ejects (jets) a coating liquid such as ink as droplets from a plurality of ejection holes (nozzles) toward a coating target such as a substrate. The droplet coating apparatus causes a plurality of droplets to land sequentially on the coating surface of the coating object with the coating head while relatively moving the coating head and the coating object, thereby forming a predetermined coating pattern.

  When manufacturing a color filter using such a droplet applying apparatus, droplets are applied to a substrate for manufacturing a color filter. In other words, red, green and blue colored inks are applied as droplets in the recesses separated by the grid-like protrusions (black matrix) provided on the surface of the substrate for producing the color filter, and applied in the recesses. A colored layer as a film is formed. The recess has a rectangular shape in plan view, and this recess corresponds to one pixel (sub-pixel) in the liquid crystal display panel.

Here, since the amount of one droplet discharged from one discharge hole is small with respect to the volume of the recess, when forming a colored layer in the recess, a plurality of droplets of colored ink are applied to one recess. The At this time, since it is necessary to form the colored layer with a uniform thickness, the target application positions (scheduled application positions) of the droplets are set at equal intervals along the longitudinal direction of the concave portion. On the other hand, droplets are sequentially applied.
Japanese Patent Laid-Open No. 9-230129

  However, since the substrate and the coating head are relatively moved during the coating operation, the droplets coated on the substrate flow in the direction opposite to the relative movement direction when landed on the substrate. However, the shape is not hemispherical but eccentric in the relative movement direction. Due to this influence, the coating film, which is an aggregate of the droplets, is not hemispherical, but has a shape eccentric in the relative movement direction. For this reason, the coating film is biased to one side in the longitudinal direction of the concave portion, the thickness of the coating film becomes non-uniform, and in some cases, the coating liquid may get over the convex portion and protrude. When the thickness of the colored layer is not uniform, color unevenness occurs in the pixel, and the display quality of the liquid crystal display panel is deteriorated. In addition, when the coating solution passes over the convex portion, if the colored layer of the adjacent pixel is a colored layer of a different color, the colors are mixed and a defective product is generated.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a droplet coating apparatus and a droplet coating method capable of improving the coating quality of a coating liquid on a coating object. .

A first feature according to the embodiment of the present invention is that in the droplet coating apparatus, a coating head that discharges the coating liquid as droplets toward the coating target;
A moving mechanism for relatively moving the said coating head and the coating object,
The coating head and the moving mechanism to, on the basis of the application information related to the target coating position of the droplet in the coating zone on the object to be coated, the coating compartment while relatively moving said coating head and the coating object It means for performing control by applying a plurality of droplets, to produce a coating film which is an aggregate of a plurality of the droplets,
It means for determining the center of gravity of the coating film,
Based on the centroid position obtained, and means for correcting the target coating position of the plurality of liquid drops with respect to the coating section,
It is to provide.

Second feature of the embodiment of the present invention is a droplet applying method, a coating head for ejecting droplets of coating liquid toward the coating object and object to be coated on the object to be coated coating while relatively moving on the basis of the application information related to the target coating position of the droplets in the compartment, a plurality of the droplet was applied to the coating compartment, generating a coating film which is an aggregate of a plurality of the droplets ,
A step of determining the center of gravity of the coating film,
Based on the centroid position obtained, the step of correcting the target coating position of the plurality of liquid drops with respect to the coating section,
It is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, the droplet coating apparatus and the droplet coating method which can improve the coating quality of the coating liquid with respect to a coating target object can be provided.

  An embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, in the droplet applying apparatus 1 according to the embodiment of the present invention, a substrate K as an application target is in a horizontal state (in FIG. 1, a state along the X-axis direction and the Y-axis direction orthogonal thereto. ), The Y-axis moving mechanism 3 that holds the moving table 2 and moves it in the Y-axis direction, and moves the moving table 2 in the X-axis direction via the Y-axis moving mechanism 3 The X-axis moving mechanism 4 to be moved, the plurality of coating heads 5 that discharge a coating liquid such as ink as droplets E1 toward the substrate K on the moving table 2, and the imaging operation toward the substrate K on the moving table 2. An imaging unit 6 to perform and a control unit 7 to control each unit are provided.

  The moving table 2 is stacked on the Y-axis moving mechanism 3 and is provided so as to be movable in the Y-axis direction. The moving table 2 is moved in the Y-axis direction by the Y-axis moving mechanism 3. The substrate K is placed on the movable table 2 by its own weight, but the present invention is not limited to this. For example, a mechanism such as an electrostatic chuck or an adsorption chuck is provided to hold the substrate K. Also good. At the end portion of the moving table 2, a discharge stabilizing portion 2 a for stabilizing the discharge of each coating head 5 is provided. The discharge stabilizing portion 2a includes a dummy discharge tray for each coating head 5, a wipe blade for wiping the discharge surface of each coating head 5, and the like.

  The Y-axis moving mechanism 3 is a moving mechanism that guides and moves the moving table 2 in the Y-axis direction. The Y-axis moving mechanism 3 is electrically connected to the control unit 7 and its driving is controlled by the control unit 7. As the Y-axis moving mechanism 3, for example, a linear motor moving mechanism using a linear motor as a driving source, a feed screw moving mechanism using a motor as a driving source, or the like is used.

  The X-axis movement mechanism 4 is a movement mechanism that guides and moves the Y-axis movement mechanism 3 in the X-axis direction. The X-axis moving mechanism 4 is electrically connected to the control unit 7 and its driving is controlled by the control unit 7. As the X-axis moving mechanism 4, for example, a linear motor moving mechanism using a linear motor as a driving source, a feed screw moving mechanism using a motor as a driving source, or the like is used.

  The coating head 5 is an inkjet head that ejects a coating liquid such as ink from a plurality of ejection holes (nozzles) N as droplets E1. The coating head 5 incorporates a plurality of piezoelectric elements (not shown) corresponding to the respective ejection holes N for ejecting the droplets E1. The respective ejection holes N are formed on the ejection surface of the coating head 5 in a straight line at a predetermined pitch (interval). For example, the number of discharge holes N is about several tens to several hundreds, the diameter of the discharge holes N is about several μm to several tens μm, and the pitch of the discharge holes N is several tens μm to several hundreds μm. Degree.

  The coating head 5 is electrically connected to the control unit 7, and its driving is controlled by the control unit 7. The coating head 5 discharges the droplet E1 from each discharge hole N according to the application of the drive voltage to each piezoelectric element. For example, the coating head 5 generates one coating film E2 with eight droplets E1. Here, the coating liquid is supplied from a liquid tank (not shown) that stores the coating liquid. This coating solution is a solution composed of a solute that remains as a residue on the substrate K and a solvent that dissolves (disperses) the solute. The solvent is, for example, volatile. In the embodiment of the present invention, for example, three types of inks of red, green, and blue are used as the coating liquid. In this case, the liquid tank has three tanks for each color, and a solution of each color is supplied to each of the application heads 5 for red, green, and blue.

  Furthermore, the coating head 5 is provided so as to be rotatable in the θ direction (rotation direction along the XY plane in FIG. 1) by a rotation mechanism (not shown). The coating head 5 is tilted by a predetermined tilt angle with respect to the relative movement direction of the relatively moving substrate K by the rotation mechanism, and coating is performed in this state. When coating is performed on the substrate K that relatively moves in the X-axis direction, the coating pitch of the droplets E1 in the Y-axis direction can be adjusted by changing the tilt angle of the coating head 5. Further, the application pitch P in the X-axis direction can be adjusted by changing the discharge frequency (discharge timing) of the droplet E1.

  The imaging unit 6 is a camera that images a plurality of coating films E2 that are aggregates of droplets E1 landed on the substrate K. One coating film E2 is an aggregate of eight droplets E1, for example. The imaging unit 6 is electrically connected to the control unit 7, and its driving is controlled by the control unit 7. For example, a CCD (Charge Coupled Device) camera or the like is used as the imaging unit 6. The imaging unit 6 functions as a detection unit that detects the shape of each coating film E2.

  The control unit 7 includes a microcomputer that centrally controls each unit, and a storage unit that stores application information related to application, various programs, and the like (none of which are shown). The application information includes a predetermined application pattern such as a dot pattern (that is, position information related to the target application position A1 of the droplet E1), information about the inclination angle of the application head 5, the discharge frequency of the application head 5, and the moving speed of the substrate K, etc. Is included.

  Next, the correction operation performed by the droplet applying apparatus 1 will be described. Note that the control unit 7 of the droplet applying apparatus 1 executes correction processing based on various programs. Here, the case where the colored layer as the coating film E2 is manufactured using the droplet coating apparatus 1 will be described.

  As shown in FIG. 2, the control unit 7 performs application on the measurement substrate K based on the application information (step S1). That is, the control unit 7 controls the Y-axis moving mechanism 3 and the X-axis moving mechanism 4 based on the application information, positions the application head 5 at the application start position facing the application surface Ka of the substrate K, and further, the X-axis While controlling the moving mechanism 4 and moving the moving table 2 in the X-axis direction, the coating head 5 is controlled to discharge the coating liquid to the coating head 5, and each of the coating surfaces Ka of the substrate K on the moving table 2 is applied to the coating surface Ka. A droplet E1 is applied.

  Here, since the measurement substrate K is a smooth glass substrate, so-called a bare glass substrate, the coating section G is not actually formed. However, in the following description, the coating section G is formed on the coating surface Ka. It is assumed that the liquid droplet E1 is applied to the virtual application section G. 3 and 4 show the measurement substrate K, but the virtual coating section G is indicated by a one-dot chain line.

  At this time, as shown in FIG. 3, the coating head 5 discharges and applies each droplet E1 toward the coating surface Ka of the substrate K moving in the X-axis direction (the arrow direction in FIG. 3). As shown in FIG. 4, a coating film E2 is generated for each coating section G on the coating surface Ka. For example, when red ink is applied to the substrate K, the droplet E1 is applied to the application section G to which the red ink is to be applied among all the application sections G, and thereafter, the green ink and the blue ink are similarly applied. Ink is also applied. Note that the coating surface Ka of the measurement substrate K is subjected to a process of repelling the coating liquid (ink repellent treatment).

  Here, each coating section G is a region corresponding to each pixel region of the color filter. That is, a black matrix as a grid-like convex portion is formed on the coated surface of the substrate for manufacturing color filters. This black matrix has ink repellency and is a grid-like black portion surrounding each of the red, green and blue pixels of the color filter. Accordingly, each coating section G is an area having the same area as the bottom surface of each of the plurality of recesses surrounded by the black matrix and located at the same place. In the substrate for manufacturing color filters, the bottom surface of each recess is It becomes the coating section G. Note that regions other than the black matrix BM on the color filter manufacturing substrate have ink affinity.

  For example, eight droplets E1 are applied in one application section G (see FIG. 3). These droplets E1 land in the coating section G on the substrate K at a predetermined coating pitch P with the target coating position A1 as a base point. Thereafter, the droplets E1 that have landed in the coating section G gather together to form a coating film E2 (see FIG. 4). Thus, the coating film E2 is generated for all the coating sections G. At this time, since the coating surface Ka of the measurement substrate K is subjected to ink repellent treatment, the spread of the droplets is suppressed, and the aggregate of the eccentric droplets having the center of gravity G has a predetermined height. It has a substantially bowl shape.

  The target application position of each of the eight droplets E1 is determined by determining the target application position A1 of the droplet E1 that first lands on the application section G within the eight droplets E1. The predetermined coating pitch P (for example, about 250 to 300 μm) is determined with A1 as a base point. The target application position A1 is defined by the XY coordinates for each application section G. Information on the target application position A1 and the predetermined application pitch P is stored in the storage unit as application information. Further, the total amount of the eight droplets E1 is set to a predetermined amount (for example, about 50 pl) that is substantially the same as the volume of the recess after the coating liquid is dried.

  Thereafter, the control unit 7 controls the imaging unit 6 to image each coating film E2 on the substrate K (step S2). That is, the control unit 7 controls the Y-axis moving mechanism 3 and the X-axis moving mechanism 4 based on the application information (application pattern), and the imaging unit is located at a position where each application film E2 generated on the substrate K can be imaged. 6 is moved to take an image of each coating film E2. The imaging unit 6 is controlled to move by a predetermined amount according to the imaging area (imaging area).

  Next, the control part 7 calculates | requires the gravity center position A2 (refer FIG. 4) of each coating film E2 based on each imaged image (step S3). For example, the center-of-gravity position A2 in two dimensions (plan view) of the coating film E2 is calculated from the shape of the coating film E2 based on the image of the coating film E2. Note that various methods can be used as the calculation method of the center of gravity position A2.

  Next, the control unit 7 corrects each target application position A1 based on the obtained center-of-gravity position A2 of each application film E2. That is, the control unit 7 calculates the amount of misalignment between the center of gravity position A2 and the center position A3 (see FIG. 4) of the coating section G in each coating film E2, and eliminates the calculated amount of misalignment (zero). The target application position A1 is corrected. For example, when the target application position A1 is (x1, y1), the center of gravity position A2 is (x2, y2), and the center position A3 is (x3, y3), the positional deviation amount is (x3-x2). , Y3-y2), (x1, y1) of the target application position A1 is shifted by (x3-x2, y3-y2), and when the coating film E2 is formed in the coating section G, the center of gravity position Correction is performed so that A2 and the center position A3 coincide. The corrected target application position A1 is stored in a storage unit provided in the control unit 7.

  Thus, in addition to the means for controlling each part, the control unit 7 obtains means for obtaining the center of gravity position A2 of the coating film E2, and means for correcting the target application position A1 for the application section G based on the obtained center of gravity position A2, that is, It functions as means for correcting the target application position A1 so that the center of gravity position A2 and the center position A3 of the application section G coincide. Thereafter, the control unit 7 performs a coating operation on the color filter manufacturing substrate based on the corrected coating information. The coating liquid is applied in the order of red, green, and blue to the application surface of the substrate for manufacturing color filters, that is, a plurality of recesses (a plurality of pixel regions) surrounded by a black matrix.

  In the correction operation described above, the target application position A1 is corrected so that the gravity center position A2 of the coating film E2 and the center position A3 of the application section G coincide with each other. Thereafter, when the droplet E1 is applied on the substrate for manufacturing the color filter, the droplet E1 is applied to the corrected target application position A1, and the gravity center position A2 of the coating film E2 and the coating section G are applied. A coating film E2 having the same center position A3 is generated as a colored layer on a substrate for manufacturing a color filter. As a result, the coating film E2 is not biased to one side in the longitudinal direction of the concave portion, and the thickness of the coating film E2 is not uniform, or the coating liquid does not protrude beyond the convex portion. Since it becomes possible, the coating quality of the coating liquid with respect to a board | substrate can be improved. In particular, the uniformity of the thickness of the coating film E2 can be improved, and as a result, the thickness of the coating film E2 as a colored layer becomes uniform. It is possible to prevent stripe irregularities, and the quality of a display panel having a color filter can be improved.

  As described above, according to the embodiment of the present invention, a plurality of liquid droplets E1 are applied on the relatively moving substrate K based on the application information related to the target application position A1 of the liquid droplets E1, and a plurality of liquids are applied. A coating film E2 that is an aggregate of droplets E1 is generated, the shape of the generated coating film E2 is imaged and detected, and the center of gravity position A2 of the coating film E2 is based on the captured image (the shape of the detected coating film E2). And the target application position A1 is corrected so that the center position A2 of the coating film E2 and the center position A3 of the application section G coincide with each other based on the obtained center position A2. A coating film E2 that is applied to the corrected target application position A1 and in which the gravity center position A2 of the coating film E2 and the center position A3 of the coating section G coincide with each other is generated on the substrate for manufacturing the color filter.

  As a result, the center of gravity of the coating film E2 does not deviate to one side in the longitudinal direction of the concave portion, and the coating liquid spreads from the center of the coating section G toward the periphery, so that the thickness of the coating film E2 becomes non-uniform. Alternatively, it is possible to prevent the coating liquid from overcoming the protrusions and thus to improve the coating quality of the coating liquid on the substrate. As a result, it is possible to prevent color unevenness from occurring in the pixel due to the uneven thickness of the colored layer, and to reduce the display quality of the display panel. In addition, the colored layer of the adjacent pixel is different. In the case of a colored layer, it is possible to prevent the coating liquid from overcoming the convex portions and mixing the colors, resulting in defective products.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  In the above-described embodiment, the target application position A1 is corrected so that the center of gravity A2 of the coating film E2 coincides with the center position A3 of the application section G. However, the present invention is not limited to this. The target application position A1 may be corrected according to the nature of the substrate for use, that is, the nature of the bottom surface of the recess. For example, referring to FIG. 3, when the bottom surface of the recess (corresponding to the coating section G) has a tendency to spread ink in the other direction as compared with one direction in the longitudinal direction, the center of gravity position A2 is located with respect to the center position A3. Thus, the target application position A1 is corrected so as to be shifted to one side in the longitudinal direction.

  In the above-described embodiment, the substrate K is moved with respect to the coating head 5. However, the present invention is not limited to this, and the coating head 5 may be moved with respect to the substrate K. In short, the coating head 5 and the substrate K may be moved relative to each other.

  In the embodiment of the present invention, the imaging unit 6 is used as the detection unit. However, the present invention is not limited to this. For example, a distance measuring device such as a laser displacement meter may be used as the detection unit. . In this case, the thickness of the coating film E2 is sequentially measured while the distance measuring device is moved relative to the coating film E2 at predetermined intervals, and the overall shape (three-dimensional shape) of the coating film E2 is determined from the thickness. And the center-of-gravity position in three dimensions may be obtained.

  Further, in the above-described embodiment, the imaging operation by the imaging unit 6 is performed after the application liquids of all colors of red, green, and blue are applied. However, the present invention is not limited to this. The imaging operation by the imaging unit 6 may be performed after applying the coating liquid for each of green and blue.

  In addition, in the above-described embodiment, the droplet applying apparatus 1 is used for manufacturing a color filter. However, the present invention is not limited to this, and the droplet applying apparatus 1 may be used other than for manufacturing a color filter. Good.

  Finally, in the above-described embodiment, various numerical values are given, but these numerical values are merely examples and are not limited.

It is a schematic diagram which shows schematic structure of the droplet coating device which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the correction | amendment operation | movement which the droplet coating device shown in FIG. 1 performs. It is explanatory drawing for demonstrating correction | amendment operation | movement shown in FIG. It is explanatory drawing for demonstrating correction | amendment operation | movement shown in FIG.

Explanation of symbols

1 Droplet coating device 3 Movement mechanism (Y-axis movement mechanism)
4 Movement mechanism (X-axis movement mechanism)
5 coating head A1 target coating position A2 center of gravity position A3 center position E1 droplet E2 coating film G coating section K coating object (substrate)

Claims (5)

An application head for discharging the application liquid as droplets toward the application object;
A moving mechanism for relatively moving the object to be coated and the coating head;
The coating head and the moving mechanism to, on the basis of the application information related to the target coating position of the droplet in the coating zone on the object to be coated, the coating compartment while relatively moving said coating head and the coating object Means for applying a plurality of liquid droplets to the substrate and generating a coating film that is an aggregate of the plurality of liquid droplets;
Means for obtaining the position of the center of gravity of the coating film;
Means for correcting a target application position of the plurality of droplets with respect to the application section based on the determined center-of-gravity position;
A droplet applying apparatus comprising:   2. The droplet applying apparatus according to claim 1, wherein the correcting unit corrects the target application position of the plurality of droplets so that the position of the center of gravity coincides with the center position of the application section. While relatively moving the application object and the application head that discharges the application liquid as droplets toward the application object based on the application information regarding the target application position of the droplets in the application section on the application object , Applying a plurality of droplets to the application section to generate a coating film that is an aggregate of the plurality of droplets;
Obtaining a center of gravity position of the coating film;
Correcting a target application position of the plurality of droplets with respect to the application section based on the determined center-of-gravity position;
A droplet coating method comprising:   4. The droplet application method according to claim 3, wherein in the correcting step, the target application position of the plurality of droplets is corrected so that the center of gravity position and the center position of the application section coincide with each other.   The droplet application method according to claim 4, wherein a positional deviation between the center of gravity position and the central position of the application section is obtained, and the target application positions of the plurality of liquid drops are corrected by the obtained positional deviation.

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