KR100717271B1 - Aligning apparatus and method of the same - Google Patents

Abstract

The present invention relates to an alignment apparatus and a method for aligning a printhead having a plurality of nozzles for performing a print job, the alignment apparatus according to the present invention includes a head transfer unit for transportably supporting the printhead; ; A transparent specimen provided below the print head and having a predetermined specimen mark that can be picked up; A first camera provided below the transparent specimen and photographing a specimen mark of the transparent specimen; A second camera coupled to the print head to photograph a specimen mark of the transparent specimen; And a controller configured to control the head transfer unit to align the second camera with the first camera by comparing the images photographed by the first camera and the second camera. Thereby, there can be provided an alignment apparatus and method thereof in which the alignment of the substrate and the printhead is relatively accurate and can be simplified.

Description

Alignment device and its method {ALIGNING APPARATUS AND METHOD OF THE SAME}

1 is a schematic perspective view showing an alignment process of an alignment apparatus according to the present invention;

2 is a comparison diagram showing an image of the specimen marks taken before and after the first and second cameras are aligned;

3 is a side view showing a process of obtaining a distance to a reference nozzle;

4 is a control block diagram of an alignment device;

5 is a combination diagram combining the image of the nozzle and the substrate photographed by the camera,

6 is a flowchart illustrating an alignment process.

<Description of the symbols for the main parts of the drawings>

10: alignment device 20: printhead

21: nozzle 23: reference nozzle

25: head transfer unit 30: transparent specimen

31: Psalm Mark 40: First Camera

50: second camera 60: substrate

61 substrate identification mark 63 pixel

65: reference pixel 67: pixel grid

70: stage 80: control unit

81: input unit 90: display unit

The present invention relates to an alignment apparatus and a method thereof, and more particularly, to an alignment apparatus and method for aligning a substrate and a printhead for performing a print operation on the substrate.

In general, a flat panel display device having a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) and an organic ELD (Electro Luminescence Display) is equipped with a display panel for forming an image.

The manufacturing process of such a display panel includes a printing process of forming a color filter, a predetermined pattern, and the like on a display panel substrate. This printing process involves screen printing, which transfers a pattern on the panel surface by passing a medium such as ink through a stencil screen with a squeeze, and a chemical reaction occurs when a specific chemical (Photo Resist) receives light. There is a photolithography method in which light is selectively irradiated to a photoresist using a mask of a pattern to be obtained using this changing principle to form the same pattern as the mask. However, in recent years, an apparatus is intensive in a printing process, and an ink jet method which uses a relatively low cost is used. The inkjet method sprays ink using a print head having an orifice on a plurality of pixels formed on a substrate for a display panel, and then cures the ink.

In the printing process using the inkjet method, an alignment apparatus for aligning the printhead with respect to the substrate such that the ink is positioned at the pixel of the substrate, or an inspection apparatus for inspecting whether the ink is positioned at the pixel of the substrate. Etc. are included. In the process of aligning and aligning the printhead and the substrate, jetting of ink to a predetermined test substrate is performed to confirm the alignment of the pixel of the printhead and the substrate. It is judged that it went well.

An inkjet alignment apparatus for manufacturing such a display panel is disclosed in Korean Laid-Open Patent Publication No. 2003-0080380 (2003.10.17). The prior art adjusts each orifice to be positioned in a grid capable of orifice alignment and through a grid drawn to the pixel pitch of the pattern of the substrate to be printed through the head. It consists of a plurality of CCD (Character Coupled Device) cameras.

With this configuration, in the prior art, a CCD camera is provided below the stage supporting the transparent substrate and photographed upward, so that the position of the orifice can be imaged through the transparent substrate. Thus, the orifice may be aligned with a grid drawn according to the pixel pitch of the pattern of the substrate through the image photographed by the CCD camera.

By the way, such a prior art has a high cost and time, such as ink and glass due to jetting in the process of jetting (Jetting) there is a fear that the economic cost increases. In addition, the structure is complicated by using a lot of CCD camera, there is a fear that a large amount of time is also required for detection, control and the like.

In addition, the prior art is provided to the lower side of the stage for supporting the substrate to shoot the substrate and the orifice through the hole formed in the stage is not easy to mount the camera and complicated configuration. In addition, the prior art can only be used for transparent substrates, so in the case of an opaque substrate it is impossible to use.

In addition, the conventional alignment device for manufacturing a display panel is to shoot the orifice through the transparent substrate, the image of the orifice may be distorted by noise or refraction in the process of shooting through the substrate, such a distorted image Precise control can be difficult.

It is therefore an object of the present invention to provide an aligning apparatus and method, in which the alignment of the substrate with the printhead is relatively accurate and can be simplified.

According to the present invention, there is provided an alignment apparatus for aligning a print head having a plurality of nozzles for performing a print job, the alignment device comprising: a head conveying portion for transportably supporting the print head; A transparent specimen provided below the print head and having a predetermined specimen mark that can be picked up; A first camera provided below the transparent specimen and photographing a specimen mark of the transparent specimen; A second camera coupled to the print head to photograph a specimen mark of the transparent specimen; And a control unit for controlling the head transfer unit to align the second camera with the first camera by comparing the images photographed by the first camera and the second camera.

Here, the controller compares the specimen mark images of the transparent specimen photographed by the first camera and the second camera while the second camera is aligned with the first camera, and whether the second camera is aligned with respect to the first camera. The method may further include judging again to align the first and second cameras more accurately.

The control unit may further include calculating a distance from the second camera to the reference nozzle of the printhead based on an image of the first camera photographing the reference nozzle of the printhead close to the second camera. It is possible to easily calculate the position of the reference nozzle, characterized in that.

In addition, a stage for transportably supporting a substrate having a plurality of pixels formed with a substrate identification mark and equal intervals; The controller may further find a reference pixel of the substrate, further comprising finding a reference pixel of the substrate based on the substrate identification mark of the substrate photographed by the second camera transferred from the transparent substrate to the substrate.

The control unit may further include controlling at least one of the head transfer unit and the stage such that a reference nozzle of the print head corresponds to a reference pixel of the substrate based on a distance calculated from the second camera to the reference nozzle. You can easily align the printheads and pixels in place.

On the other hand, an object of the present invention, in the alignment method for aligning the printhead having a plurality of nozzles for performing a print operation, provided in the lower portion of the transparent specimen having a predetermined specimen mark to remove the specimen mark of the transparent specimen Photographing by the camera; Photographing, by a second camera, a specimen mark of the transparent specimen coupled to the print head provided on an upper portion of the transparent specimen; And comparing the images photographed by the first camera and the second camera, and controlling a head transfer unit for supporting the printhead to align the second camera with the first camera. It is achieved by the printing method.

Here, by comparing the specimen mark images of the transparent specimen taken by the first camera and the second camera while the second camera is aligned with the first camera, it is determined whether the second camera is aligned with respect to the first camera. It may include the step of aligning the first and second camera more accurately.

The method may further include calculating, by the first camera, a distance from the second camera to the reference nozzle of the printhead based on an image of sequentially photographing the reference nozzle of the printhead close to the second camera. As a feature, the position of the reference nozzle can be easily calculated.

The method may further include: supporting, by a stage, a substrate having a substrate identification mark and a plurality of pixels formed at equal intervals; The reference pixel may be easily found, including the step of finding the reference pixel of the substrate based on the substrate identification mark of the substrate photographed by the second camera transferred from the transparent substrate to the substrate.

And controlling one of the head transfer unit and the stage so that the reference nozzle of the print head is aligned with the reference pixel of the substrate based on the distance calculated from the second camera to the reference nozzle. Heads and pixels can be aligned in place.

Hereinafter, the alignment apparatus 10 according to an embodiment of the present invention will be described with reference to the drawings. The present invention can be applied to the alignment apparatus 10 of various manufacturing processes. However, the embodiment will be described by way of example for use in the printing process of the display panel used in the display device for convenience of description. This printing process is a process of forming a color filter (Color Filter), a pattern and the like on the substrate 60 is configured by the inkjet method.

The alignment apparatus 10 includes a printhead 20 having a plurality of nozzles 21 for performing a print job, as shown in Figs. A head transfer part 25 supporting the print head 20 to be transferable; A transparent specimen 30 having a predetermined specimen mark 31; A first camera 40 provided below the transparent specimen 30 to photograph the specimen mark 31 of the transparent specimen 30; A second camera 50 coupled to the print head 20 provided on the transparent specimen 30 to photograph the specimen mark 31 of the transparent specimen 30; And a controller 80 for controlling the head transfer unit 25 to align the second camera 50 with the first camera 40 by comparing the images photographed by the first camera 40 and the second camera 50. do. The alignment apparatus 10 further includes: a stage 70 for transportably supporting a substrate identification mark 61 and a substrate 60 having a plurality of pixels 63 formed at equal intervals; A control unit for finding the reference pixel 65 of the substrate 60 based on the substrate identification mark 61 of the substrate 60 taken by the second camera 50 transferred from the transparent substrate 60 to the substrate 60. 80 may further include.

The printhead 20 has a plurality of nozzles 13 for injecting ink to the pixels 63 of the substrate 60, as shown in FIG. In addition, the print head 20 may be supported by the head transfer unit 25 to be moved in the two axis (X, Y) direction and rotate in the horizontal direction on the plate surface of the substrate 60.

As illustrated in FIG. 1, a plurality of nozzles 21 protrude from the print head 20. Such a nozzle 21 ejects ink for color filters having colors of R (Red), G (Green), and B (Blue), for example, when manufacturing a display panel for TFT-LCD. The nozzle 21 may employ various numbers depending on the size of the substrate 60. In addition, the nozzle 21 has a reference nozzle 21 located closest to the second camera 50, and the reference nozzle 21 serves as a reference for aligning the printhead 20 and the substrate 60. . In addition, the distance between the plurality of nozzles from the reference nozzle 21 may be input through the input unit 81 based on the information provided by the manufacturer.

As shown in FIG. 1, the head transfer part 25 supports the print head 20 so as to be transportable. In addition, the head transfer part 25 may support the print head 20 to move in the two axis (X, Y) directions and to rotate on the plate surface of the substrate 60 in the horizontal axis (Z). The head transfer unit 25 may use an LM guide (Linear Motion Guide) (not shown). Accordingly, the head transfer unit 25 transfers the print head 20 along the arrangement direction of the pixels 7 provided on the substrate 60. That is, as shown in FIG. 1, the head transfer part 25 moves the print head 20 in the X direction, so that the ink injected from the nozzle 21 may be filled in the pixel 63. Then, the head conveyer 25 moves the printhead 20 to the pixels 63 in the other rows in the Y direction and then fills the ink with the ink while moving the printhead 20 in the direction opposite to the X direction. Let's do it. At this time, the head transfer unit 25 may fill the ink in the pixel 63 of the substrate 60 by rotating the print head 20 to the plate surface of the substrate as necessary.

As shown in FIG. 1, the transparent specimen 30 has a specimen mark 31 that can be photographed and is fixed to one end of the stage 70. Thus, the transparent specimen 30 may be a reference for aligning the reference positions of the first camera 40 and the second camera 50. In addition, the transparent specimen 30 may be provided to be movable above the substrate 60 together with the first camera 40 to be described later.

As shown in FIGS. 1 to 3, the first camera 40 is provided below the transparent specimen 30 to photograph the specimen mark 31 of the transparent specimen 30. In addition, the first camera 40 photographs the reference nozzle 21 to find the reference nozzle 21 of the printhead 20. In this case, the reference nozzle 21 may be photographed using the transparent specimen 30, and the transparent specimen 30 may not be used if necessary. Thus, a deviation from the first camera 40 to the second camera 50 may be detected by the controller 80 by comparing the photographed images of the first camera 40 and the second camera 50. The controller 80 may calculate the distance from the two cameras 50 to the reference nozzle 21.

That is, referring to FIG. 2, the second camera 50 is an image of photographing the specimen mark 31, and FIG. 2A and the first camera 40 are images of photographing the specimen mark 31. Comparing FIG. 2B, the distance between the specimen marks 31 of the transparent specimens 30 is separated by “d”. Accordingly, the controller 80 moves the head transfer unit 25 by the distance “d” so that the image a and the image b coincide, that is, the second camera 50 is aligned with the first camera 40. To control. Then, in order to check the alignment of the first and second cameras 40 and 50, the second camera 50 retakes the specimen mark 31. FIGS. 2 (c) and the first camera 40. 2), the distance between the specimen marks 31 of the transparent specimens 30 coincides with each other. Here, if the image (c) and the image (d) do not match, the above-described process is repeated. Thus, since the alignment process of the first camera 40 and the second camera 50 using the transparent specimen 30 is completed, the next process may be performed, so that alignment may be performed more accurately. As shown in FIG. 3, the first camera 40 photographs the second camera 50 and the reference nozzle 21, and the controller 80 controls the reference nozzle 21 from the second camera 50. The distance spaced up to " d1 " in FIG. 3 is calculated. Here, when the distance from the second camera 50 is photographed with respect to nozzles other than the reference nozzle 21 in the first camera 40, respectively, the controller 80 controls the distance from the second camera 50 to another nozzle. The distances " d2 ", " d3 " and " d4 "

As shown in FIGS. 1 and 5, the second camera 50 is coupled to the print head 20 provided on the transparent specimen 30 to photograph the specimen mark 31 of the transparent specimen 30. . In addition, the second camera 50 photographs the substrate identification mark 61 of the substrate 60 to find the reference pixel 65 of the substrate 60. Accordingly, the controller 80 shifts from the first camera 40 to the second camera 50 and moves to the reference pixel 65 corresponding to the reference nozzle 21 in comparison with the captured image signal or input information. The distance can be calculated. Since the alignment process of the first and second cameras 40 and 50 has been described above, a description thereof will be omitted. Referring to FIG. 5, the process of finding the reference pixel 65 will now be described. The first image A of the second nozzle 50 photographed by the first camera 40 and the reference nozzle 21 of the printhead 20, and the substrate photographed by the second camera 50 ( The substrate identification mark 61 of FIG. 60 and the second image B of the reference pixel 65 are compared. Accordingly, the controller 80 considers the distance between the second camera 50 and the reference nozzle 21 and the distance between the substrate identification mark 61 and the reference pixel 65 as in the third image C. One of the head transfer unit 25 and the stage 70 may be moved to a predetermined position so that the nozzle 21 is positioned at the reference pixel 65.

Thus, two first and second cameras 40 and 50 are installed, so that the alignment process of the substrate 60 and the printhead 20 is simple and convenient, and the alignment device 10 is relatively limited. It can be easily attached and used. In addition, since the alignment of the substrate 60 and the printhead 20 is precisely performed, no jetting is required for a separate test print, thereby reducing the cost and time, thereby reducing the economic cost. Such a camera is preferably a CCD camera, which is a digital camera having excellent performance.

As shown in FIG. 1, the substrate 60 is formed of a plate-shaped glass, and is a display panel of a flat panel display device such as TFT-LCD (Thin Film Transistor-Liquid Cystal Display) and organic ELD (Electro Luminescence Display). It is used for the production of such. The substrate 60 may have various sizes, and correspondingly, the nozzle 21 of the printhead 20 may be variously changed. The substrate 60 is provided with a pixel grid 67 in which a plurality of pixels 63 are formed at equal intervals, and each pixel 63 is ejected from the nozzle 21 of the printhead 20 to be described later. Filled ink is filled. Further, a plurality of substrate identification marks 61 serving as reference points are formed on the substrate 60 so as to align the transfer direction of the print head 20 with the arrangement direction of the pixels 63 formed on the substrate 60. The substrate 60 may be provided in a transparent manner, or may be provided in a translucent or opaque manner. However, the substrate 60 may be another type of substrate provided not only for the display panel but also for injecting the ink or the like in place by an ink spraying device such as the printhead 20. In addition, pixel information such as a distance and a width between the pixels 63 of the substrate 60 may be previously provided to the user and input through the input unit 81.

As shown in FIG. 1, the stage 70 is provided below the substrate 60 in a flat plate shape so as to stably support the substrate 60. In addition, the stage 70 transferably supports the substrate 60 to align the substrate 60 with respect to the printhead 20. The stage 70 may support the substrate 60 in such a manner that the substrate identification marks 61 of the substrate 60 may be matched with respect to the transfer direction of the print head 20 in the plane direction of the substrate 60. . That is, the stage 70 may be provided to be transportable in two axis (X, Y) directions perpendicular to each other in the plate surface direction of the substrate 60, and the horizontal axis Z in the plate surface direction of the substrate 60. It may be provided to be rotatable about. Accordingly, the stage 70 supports the substrate 60, and may transfer the substrate 60 so that the substrate identification mark 61 of the substrate 60 coincides with the transfer direction of the print head 20. In addition, the two-axis (X, Y) transfer direction of the stage 70 may be set differently from the two-axis (X, Y) transfer direction of the print head 20 described above, it may be set the same.

The alignment device 10 may further include a display unit 90 for displaying images photographed from the first and second cameras 40 and 50, as shown in FIG. 4. The display unit 90 is connected to the first and second cameras 40 and 50 to display images photographed by the first and second cameras 40 and 50. For example, as illustrated in FIG. 5, the display unit 90 may include a first camera with respect to the reference nozzle 21 of the second camera 50 and the printhead 20 captured by the first camera 40. The third image C by crossing the image A, the substrate identification mark 61 of the substrate 60 captured by the second camera 50, and the second image B for the reference pixel 65. Will be displayed. That is, the display unit 90 is the third image C displayed by crossing the first image A and the second image B at the same time, and the nozzle 21 of the printhead 20 is connected to the substrate 60. It may be confirmed whether the pixel 63 is positioned correctly. Thus, the user can easily check whether the alignment is more accurate alignment of the substrate 60 and the printhead 20 can be.

As shown in FIG. 4, the controller 40 compares the image of the specimen mark 31 of the transparent specimen 30 captured by the first camera 40 and the second camera 50 to compare the image of the second mark 50. ) To control the head transfer unit 25 to align the first camera 40. Thus, the alignment of the first camera 40 and the second camera 50 can be made easily. In addition, the controller 80 may compare the photographed image of the specimen mark 31 of the transparent specimen 30 again to confirm the alignment of the first and second cameras 40 and 50. In addition, the controller 80 may perform various functions, and these functions are overlapped with the description of the alignment process, which will be described later.

With this configuration, the alignment process of the alignment apparatus 10 according to the present invention will be described with reference to FIGS. 1 and 6.

First, in the second camera transparent specimen transfer step (S110), as shown in FIGS. 1A and 6, the second camera 50 is one side or adjacent to the stage 70 by the head transfer unit 25. Move to the top of the transparent specimen 30 installed in the area. In this case, the first camera 40 is installed under the transparent specimen 30.

In the transparent specimen photographing step (S115), as shown in FIGS. 1A and 6, the first and second cameras 40 and 50 may mark the specimen mark 31 of the transparent specimen 30 as a transparent specimen ( 30) photographed from the lower and upper portions respectively.

In the first and second camera image comparison step (S120), as shown in FIG. 6, the controller 80 compares the images photographed by the first and second cameras 40 and 50 to each other to form the first and second camera images. The controller 80 calculates the shifted distance of the image photographed by the two cameras 40 and 50. This comparison process can be confirmed as an image through the display unit 90.

In the second camera alignment step (S125), as shown in FIG. 6, the first and second camera images are captured in the first and second camera image comparison steps (S120) such that the second camera 50 is positioned in the first camera 40. The head transfer unit 25 is moved by an offset distance between the images. Thus, the first and second cameras 40 and 50 may be aligned in mutual positions. In this case, the first camera 40 may be moved as needed, and the first and second cameras 40 and 50 may be aligned with each other.

In the rephotographing step (S130), as shown in FIG. 6, the transparent specimen photographing step (S115) described above by the first and second cameras 40 and 50 in a state where the second camera alignment step S125 is completed. Repeatedly, the controller 80 compares the captured images with each other. Thus, the controller 80 checks the degree of misalignment of the specimen mark 31 and proceeds to the next process if the degree of misalignment is within a predetermined error range, but repeats the re-photographing step S130 if it is out of the predetermined error range. Thus, alignment of the first and second cameras 40 and 50 can be made accurately.

In the reference nozzle distance measuring step S135, as shown in FIG. 6, the distance from the second camera 50 to the reference nozzle 21 which is the nozzle closest to the second camera 50 is the first camera 40. ) Is taken with the image taken. That is, the controller 80 may calculate the distance between the second camera 50 and the reference nozzle 21 based on the image photographed by the second camera 50 and the reference nozzle 21. In addition, if necessary, the distance between the different nozzles may be sequentially calculated by the second camera 50.

In the second camera substrate transfer step (S140), as shown in FIGS. 1 and 6, the second camera 50 is positioned at the position of the transparent specimen 30 of FIG. It is conveyed by the head transfer part 25 above the board | substrate 60 supported by 70.

In the reference pixel detection and transfer step (S145), as shown in FIG. 6, the second camera 50 checks the substrate identification mark 61 of the substrate 60 and then photographs the reference pixel 65. 80 transfers any one of the head transfer unit 25 and the stage 70 so that the positions of the reference pixel 65 and the second camera 50 coincide with each other. In addition, the control unit 80 uses the distance from the second camera 50 detected in the reference nozzle measuring step S135 to the reference nozzle 21 so that the reference nozzle 21 is correctly positioned on the reference pixel 65. At least one of the head transfer unit 25 and the stage 70 may be transferred. Information on the mutual distance between the pixels 63 is typically input by the input unit 81. However, if necessary, the second camera 50 photographs the mutual distances of the respective pixels 63, and the controller 80 may calculate the distances between the respective pixels 63. Thus, the printhead 20 and the pixel 63 can be easily aligned in position.

In the ink injection step S150, as shown in FIG. 6, ink of the nozzle 21 is ejected to fill the predetermined pixel 63 with ink.

As described above, the alignment device according to the present invention is characterized by having a transparent specimen and two cameras, so that no jetting is performed during the alignment process between the substrate and the printhead. Thus, the cost and time of the ink and glass, such as by jetting can be reduced to reduce the cost. In addition, the use of two cameras for a large display panel, such as the structure is simple, can improve the accuracy through the verification process, it can be easily applied to the existing alignment device. In addition, the distortion of the image of the orifice generated by noise or refraction caused by transmission can be reduced rather than the process of photographing through the substrate.

As described above, there can be provided an alignment apparatus and a method thereof in which the alignment of the substrate and the printhead is relatively accurate and can be simplified.

Claims (10)

An alignment apparatus for aligning a printhead having a plurality of nozzles for performing a print job, A head transfer part for supporting the print head so as to be transportable; A transparent specimen provided below the print head and having a predetermined specimen mark that can be picked up; A first camera provided below the transparent specimen and photographing a specimen mark of the transparent specimen; A second camera coupled to the print head to photograph a specimen mark of the transparent specimen; And a control unit which controls the head transfer unit to align the second camera with the first camera by comparing the images photographed by the first camera and the second camera. The method of claim 1, The control unit compares a specimen mark image of the transparent specimen photographed by the first camera and the second camera while the second camera is aligned with the first camera, and again whether or not the second camera is aligned with respect to the first camera. Alignment apparatus, characterized in that further comprising judging. The method according to claim 1 or 2, The control unit may further include calculating a distance from the second camera to the reference nozzle of the printhead based on an image of the first camera photographing the reference nozzle of the printhead close to the second camera. Alignment device. The method of claim 3, A stage for transportably supporting a substrate having a plurality of pixels formed at a substrate identification mark and at equal intervals; The controller may further include finding a reference pixel of the substrate based on a substrate identification mark of the substrate photographed by the second camera transferred from the transparent substrate to the substrate. The method of claim 4, wherein The control unit may further include controlling at least one of the head transfer unit and the stage such that a reference nozzle of the printhead corresponds to a reference pixel of the substrate based on a distance calculated from the second camera to the reference nozzle. Aligning device characterized in. An alignment method for aligning a printhead having a plurality of nozzles for performing a print job, Photographing the specimen mark of the transparent specimen under the transparent specimen having a predetermined specimen mark by the first camera; Photographing, by a second camera, a specimen mark of the transparent specimen coupled to the print head provided on an upper portion of the transparent specimen; And comparing the images photographed by the first camera and the second camera, and controlling a head transfer unit for supporting the printhead to align the second camera with the first camera. Printing method. The method of claim 6, Determining whether the second camera is aligned with respect to the first camera by comparing specimen images of the transparent specimen photographed by the first camera and the second camera while the second camera is aligned with the first camera. Alignment method comprising a. The method according to claim 6 or 7, And calculating, by the first camera, a distance from the second camera to the reference nozzle of the printhead based on an image of sequentially photographing the reference nozzle of the printhead close to the second camera. How to align. The method of claim 8, The stage supporting the substrate having a plurality of pixels formed at equal intervals with the substrate identification mark; And finding a reference pixel of the substrate based on the substrate identification mark of the substrate photographed by the second camera transferred from the transparent substrate to the substrate. The method of claim 9, And controlling one of the head transfer unit and the stage to align the reference nozzle of the print head with a reference pixel of the substrate based on a distance calculated from the second camera to the reference nozzle. How to align.

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