KR102559882B1 - Method and Apparatus for Droplet Formation - Google Patents

Abstract

In the droplet ejection method, an inkjet head having a plurality of nozzles disposed at a first interval is used. After first ejecting liquid droplets on the substrate using the inkjet head, the inkjet head is moved by a second distance consisting of (the first distance × integer multiple + first distance/2), and then the liquid droplets may be secondarily ejected on the substrate using the inkjet head moved by the second distance.

Description

Droplet ejection method and apparatus {Method and Apparatus for Droplet Formation}

The present invention relates to a droplet ejection method and method, and more particularly, to a droplet ejection method and apparatus using an inkjet head having a plurality of nozzles at regular intervals.

In recent years, in the case of printing using ink on a print medium such as paper, in the case of forming an alignment film or applying UV ink on a substrate (transparent substrate) for production of a liquid crystal display device or the like, or in the case of applying a color filter on a substrate for production of an organic EL display device or the like, a printing device having an inkjet head, that is, a droplet ejection device is used.

1 is a schematic diagram for explaining a conventional droplet ejection method.

Referring to FIG. 1 , an inkjet head 10 for discharging droplets 13 and 15 onto a substrate 11 is provided. Although not shown, a plurality of nozzles may be arranged at regular intervals in the inkjet head 10 . Accordingly, in ejection of the droplets 13 and 15 using the inkjet head 10, the droplets 13 and 15 may be ejected at regular intervals through the nozzle.

In particular, in ejecting the droplets 13 and 15 using the inkjet head 10, the droplets 13 are first ejected, then the inkjet head 10 is moved by a half distance d1 based on a predetermined distance between the nozzles, that is, the distance between nozzles, and then the droplets 15 are ejected secondarily. At this time, when two nozzles (region A) unable to eject the liquid droplets 13 and 15 are adjacent to each other, the portion (region B) where the liquid droplets 13 and 15 are not ejected occurs substantially over two lines even when the inkjet head 10 is moved by a half interval d1.

As such, when a part where the droplet is not discharged across the two lines occurs, visibility increases after baking, which causes a process defect.

Korean Registered Patent No. 10-0512229

An object of the present invention is to provide a liquid droplet ejection method and apparatus capable of sufficiently lowering visibility after curing even when a nozzle does not eject a liquid droplet among a plurality of nozzles.

In order to achieve the above object, a droplet ejection method according to an embodiment of the present invention is a droplet ejection method using an inkjet head having a plurality of nozzles arranged at a first interval, comprising: firstly ejecting droplets on a substrate using the inkjet head; moving the inkjet head by a second interval consisting of (the first interval × integer multiple + first interval/2); and secondarily ejecting liquid droplets onto the substrate using the inkjet head moved by the second interval.

In the droplet ejection method according to the aforementioned embodiment of the present invention, an integer multiple of the second interval may be an odd number.

In the liquid droplet ejection method and apparatus of the present invention, the inkjet head is moved by a second interval obtained by adding 1/2 of the first interval to an integral multiple of the first interval, which is the interval between nozzles. Accordingly, even if a nozzle does not eject liquid droplets, a portion in which liquid drops are not ejected occurs in only one line instead of two lines.

As described above, in the case of the droplet ejection method and device of the present invention, since only one line on the substrate has a portion where the droplet is not ejected, visibility is sufficiently lowered after curing, and thus process defects can be expected to be reduced. In particular, the method of the present invention can be more actively applied to liquid droplet ejection using a recent inkjet head in which the nozzle interval is narrowed and the size of the nozzle is narrowed.

1 is a schematic diagram for explaining a conventional droplet ejection method.
2 is a schematic diagram for explaining a droplet ejection method according to an embodiment of the present invention.

Since the present invention can be applied with various changes and can have various forms, embodiments will be described in detail in the text. However, this is not intended to limit the present invention to a specific form disclosed, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numbers have been used for like elements in describing each figure. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another. Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "comprise" or "consisting of" are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, but it should be understood that the presence or addition of one or more other features or numbers, steps, operations, components, parts, or combinations thereof is not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application.

Example

First, the droplet ejection device to achieve the droplet ejection method of the present invention forms an alignment film or applies UV ink on a substrate for manufacturing a liquid crystal display device or the like, or applies a color filter on a substrate for manufacturing an organic EL display device. It can be used to apply.

The droplet ejection device may include a base, a substrate support member, a gantry, a gantry moving unit, an inkjet head moving unit, an ink supplying unit, a control unit, a droplet discharge amount measuring unit, a nozzle inspection unit, an inkjet head cleaning unit, and the like, although not shown together with an inkjet head described later.

Hereinafter, a droplet ejection apparatus for achieving the droplet ejection method of the present invention, including the inkjet head, will be described in detail.

As mentioned above, the droplet ejection device of the present invention may include an inkjet head. And, the inkjet head may be disposed in a reservoir. In particular, the inkjet head may be provided to be disposed under the reservoir. The reservoir is a member that receives and stores ink for ejecting liquid droplets on a substrate from the outside and supplies the ink to the inkjet head when a process for ejecting liquid drops is performed.

A plurality of nozzles capable of ejecting liquid droplets onto a substrate may be provided on a lower surface of the inkjet head. The inkjet head may include 128 or 256 nozzles. The nozzles may be arranged in a row at regular intervals, and may be provided to discharge droplets in an amount of pl (picoliter) units.

The number of piezoelectric elements corresponding to the number of piezoelectric elements may be provided in the nozzles of the inkjet head, and liquid droplets may be ejected onto the substrate through the nozzles by operation of the piezoelectric elements. That is, when 128 nozzles are provided, 128 piezoelectric elements are also provided, and when 256 nozzles are provided, 256 piezoelectric elements are also provided. In addition, the amount of droplets discharged from the nozzle may be independently adjusted by controlling the voltage applied to the piezoelectric elements.

Hereinafter, the droplet ejection method of the present invention using the droplet ejection device having the inkjet head will be described in detail.

2 is a schematic diagram for explaining a droplet ejection method according to an embodiment of the present invention.

Referring to FIG. 2 , an inkjet head 20 for discharging droplets 23 and 25 onto a substrate 21 is provided. Although not shown, a plurality of nozzles may be arranged at a first interval in the inkjet head 20 . Accordingly, in ejection of the droplets 23 and 25 using the inkjet head 20, the droplets 23 and 25 may be ejected at first intervals through the nozzle.
In particular, the inkjet head 20 of the liquid droplet ejection apparatus according to the present invention, in which a plurality of nozzles are disposed at a first interval, may be controlled to discharge the droplets 25 secondarily onto the substrate 21 by first ejecting the droplets 23 onto the substrate 21 and then moving the liquid droplets 23 secondarily onto the substrate 21 by a second interval consisting of (the first interval × integer multiple + first interval/2), wherein the integer multiple at the second interval may be an odd number.

As in the present invention, in ejection of the droplets 23 and 25 using the inkjet head 20, after first ejecting the droplets 23, the inkjet head 20 moves the inkjet head 20 by a second distance d2 obtained by adding 1/2 of the first distance to the multiplication of the first distance × integer multiple + first distance / 2 by an integer multiple of the first distance based on the first distance of the nozzle 2 Droplets 25 are discharged by car. In addition, it is preferable that the integer multiple in the second interval d2 is an odd number. Therefore, in the droplet ejection method of the present invention, the movement of the inkjet head 20 to secondarily eject the droplets 25 may be performed three and a half times, five times and so on based on the first interval.

As described above, when the inkjet head 20 is moved at the second distance d2 after first ejecting the droplet 23 and secondarily ejects the droplet 25, even if two nozzles (region C) not ejecting the droplet are provided adjacent to each other, the inkjet head 20 is moved by the second distance d2, so that the part (region D) where the droplets 23 and 25 are not ejected (region D) occurs on only one line. That is, in the prior art, two lines are generated adjacent to each other, but in the present invention, each of one line is generated far from each other.

Therefore, in the case of the droplet ejection method of the present invention, since only one line on the substrate 21 has a portion (region D) where the droplets 23 and 25 are not ejected, the visibility after curing can be sufficiently lowered.

Since the liquid droplet ejection method of the present invention can significantly reduce process defects even if there is a nozzle that does not discharge liquid droplets, process reliability can be improved, and furthermore, cost reduction for resolving process defects can be expected.

In addition, since the method of the present invention can be applied to liquid droplet ejection using an inkjet head having a narrow nozzle interval and a narrow nozzle size, it can be suitable for manufacturing requiring high usage.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be understood that it can be changed.

10, 20: inkjet head 11, 21: substrate
13, 15, 23, 25: droplets

Claims (4)

A droplet ejection method using an inkjet head having a plurality of nozzles disposed at a first interval, comprising:
firstly discharging liquid droplets onto a substrate using the inkjet head;
Moving the inkjet head by a second interval consisting of (the first interval × integer multiple + first interval / 2) when it is determined that two nozzles that cannot discharge the droplets among the plurality of nozzles are adjacent to each other as a result of the first discharge of the droplets; and
secondarily ejecting droplets onto the substrate using the inkjet head moved by the second interval;
The first and second liquid droplets may be discharged using the inkjet head to the substrate through each of the plurality of nozzles by controlling a voltage applied to each of a plurality of piezoelectric elements provided to correspond to each of the plurality of nozzles, and the movement of the inkjet head by a second distance may be performed to move along the longitudinal direction of a gantry to which the inkjet head is coupled so that the inkjet head may be positioned above the substrate, wherein the longitudinal direction of the gantry is The liquid droplet ejection method, characterized in that the direction perpendicular to the direction in which the substrate is transported. The method of claim 1, wherein an integer multiple of the second interval is an odd number. A droplet ejection device including an inkjet head having a plurality of nozzles arranged at a first interval,
The inkjet head is controlled to eject liquid drops secondarily onto the substrate by first ejecting liquid droplets onto the substrate and then moving them by a second distance consisting of (the first distance × integer multiple + first distance/2) when two nozzles that cannot eject the liquid drops among the plurality of nozzles are found to be adjacent to each other as a result of the first discharge of the liquid drops;
The first and second droplet discharge using the inkjet head may be performed so as to discharge the liquid droplet to the substrate through each of the plurality of nozzles by controlling a voltage applied to each of a plurality of piezoelectric elements provided to correspond to each of the plurality of nozzles, and the movement of the inkjet head by a second distance may be provided to move along the longitudinal direction of a gantry to which the inkjet head is coupled and disposed so that the inkjet head is positioned above the substrate, the length of the gantry The liquid droplet ejection device, characterized in that the direction is perpendicular to the direction in which the substrate is transported. 4. The droplet ejection device according to claim 3, wherein an integer multiple of the second interval is an odd number.

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