KR20220022493A - Apparatus for jetting ink and method for inspecting jetting stated of inkjet head - Google Patents

Abstract

The present invention provides a method for inspecting a discharge state of an inkjet head. According to one embodiment of the present invention, the method for inspecting the discharge state of the inkjet head comprises: a step of relatively moving a substrate for inspection and the inkjet head under a condition equal to a manufacturing process of an electronic device and applying ink on the substrate for inspection to form a pattern for inspection; a step of filming the pattern for inspection formed on the substrate for inspection by using a camera; and a step of inspecting, by an image data processing apparatus, the discharge state of the ink by using image data of the pattern for inspection acquired by the camera.

Description

The method of inspecting the discharge state of an ink application device and an inkjet head

The present invention is an inkjet method, for example, a color filter, a liquid crystal panel alignment film, an organic EL element, a thin film transistor, a wiring board, an ink liquid discharge state of an inkjet head used in an ink application apparatus for manufacturing electronic devices such as microlenses of the inspection method.

As a method of manufacturing a color filter used in a color liquid crystal display, a method of forming a colored layer (pixel portion) by spraying a colored ink by an inkjet method has been proposed.

Such an inkjet method has advantages such as simplicity, low cost, and a small amount of ink used. However, since the volume of the ink droplet discharged from the nozzle of the inkjet head is small and the surface area per unit volume is also large, the solvent constituting the ink is easily evaporated. For this reason, the problem that the component contained in ink deposits on the nozzle surface, the nozzle clogs and ink does not come out, and the problem that an impact position is changed from the target impact position are easy to occur. In order to minimize the occurrence of other color filter defects in the manufacture of such color filters, various methods for detecting ejection defects of the inkjet head have been proposed.

As an example, the substrate (eg, a material such as glass or film) and the inkjet head are not moved (Static), and 10 or more droplets are discharged to inspect the impact state. Since this method is not the same as the actual printing conditions, the user may not be able to print as desired by correcting it.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of accurately detecting a discharge defect of an inkjet head that may cause product defect in an ink application process in an electronic device manufacturing process by the inkjet method. do.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of predicting the ink landing position and the landing ink amount in an actual process.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of increasing correction accuracy.

The problem to be solved by the present invention is not limited to the above-mentioned problems, and the problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification and accompanying drawings. will be.

The present invention provides a method of inspecting a discharge state of an inkjet head. In an embodiment, the method of inspecting the discharge state of the inkjet head relatively moves the inspection substrate and the inkjet head under the same conditions as in the manufacturing process of the electronic device, and injecting ink onto the inspection substrate under the same conditions as in the manufacturing process of the electronic device. Forming a pattern for inspection by impact; imaging the inspection pattern formed on the inspection substrate using a camera; and the image data processing apparatus inspecting the ejection state of the ink using the image data of the inspection pattern acquired by the camera.

In an embodiment, the camera may be disposed on the inspection substrate.

In an embodiment, the camera may be provided as a line scan camera.

In an embodiment, the image data processing apparatus compares the normal impact position of the ink with the inspection impact position of the ink, and when the difference between the normal impact position and the inspection impact position is equal to or greater than a preset threshold, the inkjet head The method may further include determining that it is defective, and calculating a position correction amount of the inkjet head based on the difference between the normal impact position and the inspection impact position.

The present invention also provides an ink application device. In one embodiment, the ink is supplied to the plurality of inkjet heads having a nozzle surface for discharging the ink to the upper surface of the substrate in the form of droplets; a driving unit for relatively moving at least one of the inkjet heads and the substrate; a camera provided downstream in a relative movement direction between the inkjet head and the substrate to capture an inspection pattern formed on the substrate;

an image data processing apparatus for inspecting a discharge state of the ink liquid by using the image data of the inspection pattern acquired by the camera; and a controller for controlling at least one of the inkjet head, the driving unit, the camera, and the image data processing apparatus, wherein the controller relatively moves the inkjet head and the inspection substrate under the same conditions as in a manufacturing process of an electronic device. and control to form an inspection pattern by striking the ink on the inspection substrate,

The image data processing apparatus inspects the ejection state of the inkjet head, which includes the step of inspecting the ejection state of the ink by using the image data of the inspection pattern acquired by the camera.

In an embodiment, the camera may be disposed on the inspection substrate.

In an embodiment, the camera may be provided as a line scan camera.

In an embodiment, the image data processing apparatus compares the normal impact position of the ink with the inspection impact position of the ink, and when the difference between the normal impact position and the inspection impact position is equal to or greater than a preset threshold, the inkjet head It is judged that it is defective, and based on the said difference of the said normal impact position and the said test|inspection impact position, the position correction amount of the said inkjet head can be computed.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of accurately detecting a discharge defect of an inkjet head that may cause product defect in an ink application process in an electronic device manufacturing process by the inkjet method. do.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of predicting the ink landing position and the landing ink amount in an actual process.

An object of the present invention is to provide an inspection method and an inspection apparatus capable of increasing correction accuracy.

The effects of the present invention are not limited to the above-described effects, and the effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the present specification and accompanying drawings.

1 is a view showing a schematic configuration of an ink application apparatus according to the present invention.
2 is a flowchart illustrating a method of correcting a dot of an inkjet head using an ink application apparatus and an inspection apparatus according to an embodiment of the present invention.
3 illustrates an example of an imaged inspection pattern according to an embodiment.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings, and in the description with reference to the accompanying drawings, the same or corresponding components are given the same reference numbers regardless of reference numerals, and overlapping A description will be omitted.

Hereinafter, a facility for applying a treatment liquid to an object by an inkjet method for discharging droplets and a method for applying the treatment liquid to an object using the same will be described.

For example, the object may be a color filter (CF) substrate or a thin film transistor (TFT) substrate of a liquid crystal display panel, and the treatment liquid is liquid crystal, an aligning agent, and a red (R) pigment particle mixed in a solvent. , green (G), and blue (B) ink. As the aligning agent, polyimide may be used.

The aligning agent may be applied to the entire surface of the color filter (CF) substrate and the thin film transistor (TFT) substrate, and the liquid crystal may be applied to the entire surface of the color filter (CF) substrate or the thin film transistor (TFT) substrate. Ink may be applied to the inner region of a black matrix arranged in a grid-like pattern on a color filter (CF) substrate.

Referring to FIG. 2 , the ink applying device 110 is a device for applying ink to the surface of a substrate S by an inkjet method, and includes a steel base 116 and a stage 112 disposed on the base 116 . and a head assembly 200 having a plurality of inkjet heads 210 disposed on the stage 112 and applying liquid crystal to the surface of the substrate S seated on the stage 112, and the head assembly 200. It may include a gantry 114 for supporting it. In addition, the ink application apparatus 110 may include a plurality of vibration-proof members 113 for blocking vibration between the base 116 and the stage 112 .

The head assembly 200 may be provided as a multi-head array (MHA) unit. The head assembly 200 includes a plurality of inkjet heads 210 ( 210a to 210c ) for discharging liquid crystal in an inkjet method, a bracket 202 in which the inkjet heads 210 are installed, and the bracket 202 is coupled to the head assembly. and a driving unit 204 for moving 200 in at least one direction.

A plurality of inkjet heads 210 may be installed in two rows, for example, on the front and rear surfaces of the bracket 202 . That is, a plurality of inkjet heads 210 are arranged side by side on both front and rear side surfaces of the bracket 202 in the Y-axis direction. Each of the inkjet heads 210 is connected to a liquid crystal supply unit ( 105 in FIG. 1 ) to receive liquid crystals. Each of the inkjet heads 210 may receive the same or different liquid crystals.

The inkjet head 210 is a device for discharging liquid crystal to the surface of the substrate S, and each of the inkjet heads 210 is provided at a lower end thereof. The head has a nozzle surface in which a plurality of nozzles (not shown) for supplying liquid crystal to the substrate S are provided on a lower surface opposite to the surface of the substrate S. Each of the nozzles individually discharges the liquid crystal to the substrate (S).

When the object is a substrate S for a color filter, the inkjet heads 210 supply any one of liquid crystals of R color, G color, and B color, respectively. At this time, the droplets are inks of color R, color G, and color B. Inkjet heads 210 for supplying droplets of color R, color G, and color B, respectively, are disposed adjacent to each other.

The driving unit 204 includes first guide members 150 and 152 and the head assembly 200 coupled to the bracket 202 on which the inkjet heads 210 are installed to move the head assembly 200 in a first direction. It includes a second guide member 206 for moving in the second direction, and a driving unit (not shown). The drive unit 204 is moved along the support 114 in a first direction (ie, Y-axis) or in a second direction (ie, X-axis). Also, the driving unit 204 moves the head assembly 204 in the third direction (ie, the Z axis). Also, the driving unit 204 rotates about the central axis of each of the inkjet heads 210 .

The stage 112 is provided with a granite plate, the chucking unit 120 is disposed on one upper side to chuck the substrate S, and a cleaning unit (not shown) disposed on the other side of the upper side to clean the head assembly 200 . city) is included. The chucking unit 120 is moved along the third guide rail 122 by the chuck driving unit 126 to receive the substrate S, and when the substrate S is seated, it is chucked to apply liquid crystal to the substrate S. It includes a chuck 124 that moves to , a chuck driving unit 126 that moves or rotates the chuck 124 in at least one linear direction, and a third guide rail 122 that linearly moves the chuck 124 . . The lower part of the chuck 124 is coupled to the chuck driving unit 126 to linearly move along the third guide rail 122 in the Y-axis direction.

First guide members 150 and 152 are installed on the stage 112 to correspond to both ends of the support 114 . The first guide members 150 and 152 extend along the Y-axis direction to have the same width as the stage 112 . The first guide members 150 and 152 are provided at both upper ends of the stage 112 along the Y-axis direction to linearly move the support 114 in the Y-axis direction.

The support 114 is coupled to the driving unit 204 on one side and the sliders 154 are coupled to the lower sides of both sides to move the head assembly 200 in the Y-axis or X-axis direction. To this end, the support 114 is a driving device for driving the second guide member 206 and the driving unit 204 to move along the second guide member 206 so as to linearly move the head assembly 200 in the X-axis direction. (not shown) (eg, a motor, a gear, a pulley, a belt, a ball screw, a linear motor) and the like. An operation of the ink application apparatus 110, for example, a pressure control unit 118 for controlling general operations, such as pressure control, liquid crystal supply and discharge, is installed on one upper side of the support 114 . The support 114 has the same width as the stage 112 in the X-axis direction. That is, the support 114 is coupled to the slider 154 at both lower ends, and the slider 154 is provided to be movable in the Y-axis direction along the first guide members 150 and 152 . In addition, the support 114 linearly moves the driving unit 204 in the X-axis direction to move the head assembly 200 in the X-axis direction.

In addition, the pressure controller 118 includes a meniscus pressure control (MPC) unit for adjusting the internal pressure of the inkjet head 210 . The pressure controller 118 adjusts the internal pressure of the inkjet head 210 to a negative pressure, and when liquid crystal is supplied, individually controls a plurality of piezoelectric elements (not shown) to uniformly discharge liquid crystal from each nozzle. do.

The substrate S and the inkjet head 210 are provided to move relative to each other. When the inkjet head 210 is stationary, the substrate S moves and drops droplets on the substrate S, and when the substrate S is stationary, the inkjet head 210 moves and the liquid falls on the substrate S. You can also drop enemies. In this specification, a method of manufacturing an electronic device by dropping droplets on the substrate S while the substrate S moves in the +Y axis and the inkjet head 210 is stationary will be described as an example.

As the substrate S moves in the +Y axis, the inkjet head 210 ejects droplets to make an impact on the substrate S, and then includes a camera 400 for inspecting the impact state. There is no particular limitation on the shape of the camera 400 , but in an embodiment of the present invention, it is provided as a line scan camera. The camera 400 may be provided to be fixed in one position or may be installed to be movable as needed. For example, the camera 400 may be provided coupled to a gantry 114 , or coupled to an upper wall of a chamber in which an ink application device (not shown) is provided. The camera 400 is provided above the substrate S, and the camera 400 captures an upper surface of the substrate S.

The camera 400 is connected to the image data processing device 450 . The camera 400 constitutes an image data processing device 450 and an inspection device. The image data processing apparatus 450 analyzes the impact image of the imaged dot, and determines the state (for example, good or bad) of a nozzle. The image data processing apparatus 450 obtains the image data received from the camera 400 , analyzes the image data, and calculates information about an ink liquid discharge state.

2 is a flowchart illustrating a method of correcting a dot of an inkjet head using an ink application apparatus and an inspection apparatus according to an embodiment of the present invention. A method of correcting a dot of an inkjet head according to an embodiment of the present invention will be described with reference to FIG. 2 .

First, a pattern for inspection is formed by discharging droplets while relatively moving the substrate S and the inkjet head 210 (S10). Formation of the pattern for inspection WHEREIN: It is preferable to carry out under the same conditions as the manufacturing process for producing an electronic device product. In an embodiment, the inkjet head 210 may eject the droplet once while moving the substrate S. An inspection pattern formed by discharging droplets on the substrate S is captured by the camera 400 (S20). The image data processing apparatus 450 analyzes the dots of the imaged inspection pattern ( S30 ). The data derived through the dot analysis include data such as non-discharge of the droplet, the location of the dot, and the amount of the discharged droplet. In an embodiment, the same conditions as the manufacturing process for producing the electronic device product refer to the relative movement speed between the substrate S and the inkjet head 210 and all process conditions set in the atmosphere (temperature, pressure, airflow, etc.) it means.

The controller (not shown) calculates a correction amount required for the inkjet head 210 based on the analysis data of the image data processing apparatus 450 and corrects the inkjet head 210 ( S40 ). The correction may include correction of droplet ejection timing, correction of head position, correction of ejection amount, and the like.

3 illustrates an example of an imaged inspection pattern according to an embodiment. Referring to FIG. 3 , RX1, RX2 composed of rows as a virtual reference line, and RY1, RY2, RY3... For RYn, it is determined whether it is located at the intersection of the reference row and the reference column. The intersection of a reference row and a reference column is formed in the normal impact position. For example, the center of the dot A is at a position slightly deviated from the intersection of the reference row and the reference column. The center of the B dot is located at the intersection of the reference row and the reference column. If the center of the A dot is calculated as deviating from the preset threshold value or more at the intersection of the reference row and the reference column (normal impact position), this determines the defect of the head ejecting the A dot, and determines the nozzle state of the inkjet head 210 Maintenance or correction for changing the ejection conditions of the inkjet head 210 is performed.

The substrate S according to an embodiment of the present invention may be glass provided as a substrate for inspection. Also, as an example, the substrate S may be a film serving as a substrate for inspection.

The present invention is a method of discharging in a state most similar to the manufacturing process of an actual electronic device and inspecting the state when inspecting the impact state of a droplet ejected from an ink application apparatus. Through the inspection according to an embodiment of the present invention, the state of the inkjet head and the nozzle can be checked during ink ejection, and the ejection can be corrected to ensure accuracy.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (8)

A method for inspecting the discharge state of an inkjet head, the method comprising:
forming an inspection pattern by relatively moving the inspection substrate and the inkjet head under the same conditions as in the manufacturing process of the electronic device, and landing the ink on the inspection substrate under the same conditions as in the manufacturing process of the electronic device;
imaging the inspection pattern formed on the inspection substrate using a camera; and
and inspecting, by the image data processing apparatus, the ejection state of the ink by using the image data of the inspection pattern acquired by the camera. According to claim 1,
The camera is disposed on the inspection substrate, the discharge state inspection method of the inkjet head. According to claim 1,
The camera is an inkjet head ejection state inspection method provided as a line scan camera. According to claim 1,
The image data processing apparatus compares the normal impact position of the ink and the inspection impact position of the ink, and if the difference between the normal impact position and the inspection impact position is equal to or greater than a preset threshold, it is determined that the inkjet head is defective;
The discharge state inspection method of the inkjet head further comprising the step of calculating the position correction amount of the said inkjet head based on the said difference between the said normal impact position and the said test|inspection impact position. In the ink application device,
a plurality of inkjet heads receiving ink and discharging the ink to the upper surface of the substrate in the form of droplets;
a driving unit for relatively moving at least one of the inkjet heads and the substrate;
a camera provided downstream in a relative movement direction of the inkjet head and the substrate to capture an inspection pattern formed on the substrate;
an image data processing apparatus for inspecting the discharge state of the ink by using the image data of the inspection pattern acquired by the camera; and
a controller for controlling at least one of the inkjet head, the driving unit, the camera, and the image data processing device;
The controller is
Controlling the inkjet head and the substrate for inspection to be relatively moved under the same conditions as in the manufacturing process of the electronic device, and to form an inspection pattern by landing the ink on the substrate for inspection,
and the image data processing apparatus inspecting the ejection state of the ink by using the image data of the inspection pattern acquired by the camera. 6. The method of claim 5,
The camera is disposed on the upper portion of the inspection substrate, the ink application device. 7. The method of claim 6,
The camera is an ink application device provided as a line scan camera. 7. The method of claim 6,
The image data processing apparatus compares the normal impact position of the ink and the inspection impact position of the ink, and if the difference between the normal impact position and the inspection impact position is equal to or greater than a preset threshold, it is determined that the inkjet head is defective;
The ink application apparatus which computes the position correction amount of the said inkjet head based on the said difference of the said normal impact position and the said test|inspection impact position.

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