Inkjet printing apparatus and inkjet printing method using the same

Abstract

Disclosed are an inkjet printing apparatus and an inkjet printing method using the same. The inkjet printing apparatus according to an embodiment includes a worktable on which an object substrate including a plurality of panel regions is loaded, a substrate rotating unit located on the worktable and tilting the object substrate, and an inkjet head located above the worktable and including a plurality of nozzles that eject ink, the substrate rotating unit being tilted so that a traveling direction of the inkjet head and a first side of the object substrate form a first angle or less, the first angle (θ1) being derived from Equation 1 below. θ1 = tan ‑1 (W2 / W1) (Equation 1), in which Equation 1, W1 is a length of the first side of the object substrate, and W2 is a width of the inkjet head.

Description

Technical Field

[0001] The present disclosure relates to an inkjet printing device and an inkjet printing method using the same. Background Art

[0002] Display devices, which display images, include liquid crystal displays (LCDs) and organic light emitting diodes (OLEDs). These devices are used in various electronic devices, including mobile phones, navigation systems, digital cameras, e-books, portable game consoles, and various terminals.

[0003] In the process of manufacturing such a display device, an inkjet printing process may be used to form layers such as an organic light emitting layer, a color filter, and the like. Summary of the Invention

[0004] Embodiments provide an inkjet printing device that increases nozzle utilization by increasing the number of nozzles ejecting ink during a single inkjet process. This provides an inkjet printing device including nozzles that exhibit stable ejection conditions. Furthermore, an inkjet printing process utilizing this inkjet printing device is provided, which exhibits improved reliability.

[0005] An inkjet printing apparatus according to one embodiment includes: a worktable for mounting a target substrate including a plurality of panel areas; a substrate rotating unit located on the worktable and configured to tilt the target substrate; and an inkjet head located above the worktable and configured to include a plurality of nozzles for ejecting ink, wherein the substrate rotating unit is tilted so that a travel direction of the inkjet head and a first side of the target substrate form an angle of less than or equal to a first angle, wherein the first angle is derived from the following equation 1:

[0006] θ1=tan -1 (W2 / W1) Formula 1,

[0007] In the above formula (1), θ1 is the first angle, W1 is the length of the first side of the target substrate, and W2 is the width of the inkjet head.

[0008] The first side may be parallel to the moving direction of the inkjet head when the target substrate is not tilted.

[0009] The first side may have an inclination greater than a second angle relative to the second direction, which is the moving direction of the inkjet head, and the second angle may be derived from the following formula 2:

[0010] θ2=tan -1(1 / the number of pixel regions arranged along the second direction based on one column included in one panel region) Formula 2,

[0011] In the above formula 2, θ2 is the second angle.

[0012] The number of the pixel regions arranged along the second direction with one panel region among the plurality of panel regions as a reference may be 1,000 to 4,000.

[0013] It may be that the second angle is 0.01432 degrees (°) to 0.05373 degrees (°).

[0014] The nozzles may include a first nozzle group that ejects ink in a process in which the inkjet head moves once in a traveling direction.

[0015] It may be that the width occupied by the first nozzle group is greater than the width of one pixel area.

[0016] The width occupied by the first nozzle group may be equal to or smaller than a distance between a virtual first line formed by first vertices and a virtual second line formed by second vertices of a plurality of pixel regions located in the same column.

[0017] The inkjet printing device may include a plurality of first nozzle groups, and unused nozzles may be arranged between the plurality of first nozzle groups.

[0018] An inkjet printing method according to one embodiment includes: placing a target substrate including a plurality of panel areas on a workbench; tilting the target substrate at a first angle or less; and placing an inkjet head on the target substrate, wherein the inkjet head ejects ink through a plurality of nozzles. The first angle is an angle formed by a moving direction of the inkjet head and a first side of the tilted target substrate. The first angle is derived from the following equation 1:

[0019] θ1=tan -1 (W2 / W1) Formula 1,

[0020] In the above formula (1), θ1 is the first angle, W1 is the length of the first side of the target substrate, and W2 is the width of the inkjet head.

[0021] It may be that, in a process in which the inkjet head moves once in the second direction, the plurality of nozzles include a first nozzle group that ejects ink.

[0022] It may be that the first nozzle groups are arranged continuously.

[0023] Unused nozzles may be arranged between the plurality of first nozzle groups arranged in series.

[0024] According to embodiments, nozzle utilization can be increased by increasing the number of nozzles ejecting ink during a single inkjet process. This allows for the provision of an inkjet printing apparatus including nozzles that exhibit a stable ejection state. Furthermore, an inkjet printing process utilizing such an inkjet printing apparatus can be provided with improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a perspective view of an inkjet printing device according to one embodiment.

[0026] Figure 2 is a schematic plan view of a print head unit according to an embodiment.

[0027] Figure 3 is a schematic diagram illustrating the operation of a print head unit according to an embodiment.

[0028] Figure 4 is a sequence diagram of an inkjet printing method according to an embodiment.

[0029] Figure 5 FIG. 1 is a schematic diagram related to a method for manufacturing a display panel using an inkjet printing device according to an embodiment.

[0030] Figure 6 It is a schematic diagram related to a method for manufacturing a display panel using an inkjet printing method according to a comparative example.

[0031] (Explanation of Reference Numerals)

[0032] SUB: Substrate STA: Workbench

[0033] RL: Substrate rotation unit IH: Inkjet head

[0034] NZ: Nozzle NZ1: First nozzle group DETAILED DESCRIPTION

[0035] Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that a person having ordinary knowledge in the technical field to which the present invention pertains can easily implement the present invention. The present invention can be implemented in many different ways, but is not limited to the embodiments described herein.

[0036] In order to clearly explain the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0037] The sizes and thicknesses of the various structures shown in the drawings are arbitrarily illustrated for ease of explanation, and the present invention is not necessarily limited to the figures. In the drawings, the thicknesses of various layers and regions are exaggerated to clearly illustrate the various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for ease of explanation.

[0038] Furthermore, when a portion such as a layer, film, region, or plate is stated to be "on" or "above" another portion, this includes not only the case where it is "directly" "on" the other portion, but also the case where there is another portion intervening therebetween. Conversely, when a portion is stated to be "directly" "on" another portion, this refers to the case where there is no intervening portion. Furthermore, when a portion is stated to be "on" or "above" a reference portion, it refers to the case where it is above or below the reference portion, and does not necessarily mean that it is "on" or "above" the side opposite to the force of gravity.

[0039] Furthermore, throughout the specification, when a certain part is expressed as “including” a certain constituent element, unless otherwise stated, this means that other constituent elements are not excluded but may be included.

[0040] In addition, throughout the specification, when the expression "on a plane" is used, it means the case where the object portion is viewed from above, and when the expression "on a cross section" is used, it means the case where a cross section of the object portion is viewed vertically from the side.

[0041] Below, refer to Figures 1 to 3 A printing device according to an embodiment is described. Figure 1 is a perspective view of an inkjet printing device according to an embodiment, Figure 2 is a schematic plan view of a printing head unit according to an embodiment, Figure 3 is a schematic diagram illustrating the operation of a print head unit according to an embodiment.

[0042] Figure 1 A first direction DR1, a second direction DR2, and a third direction DR3 are defined in the figure. The first direction DR1 and the second direction DR2 are located in the same plane and are orthogonal to each other. The third direction DR3 is a direction perpendicular to the first direction DR1 and the second direction DR2. It can be understood that the first direction DR1 refers to the horizontal direction in the figure, the second direction DR2 refers to the vertical direction in the figure, and the third direction DR3 refers to the upward and downward directions in the figure.

[0043] Reference Figures 1 to 3 According to one embodiment, an inkjet printing apparatus IP includes a print head unit HU including a plurality of inkjet heads IH and a substrate rotating unit RL. The inkjet printing apparatus IP may further include a base frame BF and a work stage STA.

[0044] The base frame BF may include a support portion SUP and a head moving unit HTU. The support portion SUP may include a first support portion SUP1 extending in a horizontal first direction DR1 and a second support portion SUP2 connected to the first support portion SUP1 and extending in a vertical third direction DR3.

[0045] The head movable unit HTU may include a head movable portion HT suspended from a first support portion SUP1 and movable in one direction, and a head fixing portion HF disposed below the head movable portion HT and having a print head unit HU disposed thereon. The head movable portion HT may be movable in a first direction DR1 on the first support portion SUP1, and the print head unit HU may be fixed to the head fixing portion HF and move in the first direction DR1 together with the head movable portion HT.

[0046] like Figure 2 As shown, the print head unit HU may include a plurality of inkjet heads IH and be arranged on a base frame BF. The print head unit HU may eject predetermined ink onto a target substrate SUB using the inkjet heads IH connected to separate ink storage units.

[0047] The print head unit HU may be spaced apart from the work table STA below the base frame BF by a certain distance. The distance between the print head unit HU and the work table STA may be adjusted by the height of the second support portion SUP2 of the base frame BF.

[0048] The plurality of inkjet heads IH may be spaced apart from each other in one direction and arranged in one row or a plurality of rows. Figure 2 , the inkjet heads IH are arranged in two rows, with the inkjet heads IH in each row staggered. However, the arrangement is not limited thereto, and the inkjet heads IH may be arranged in a greater number of rows, not staggered but overlapping. The shape of the inkjet heads IH is not particularly limited, but as an example, the inkjet heads IH may have a quadrilateral shape.

[0049] Although only six inkjet heads IH arranged in the print head unit HU are shown in the figure, this is a diagram schematically showing the print head unit HU, and the number of inkjet heads IH is not limited to this.

[0050] The inkjet head IH disposed in the print head unit HU can eject ink onto the target substrate SUB disposed above the work table STA. According to one embodiment, the print head unit HU can move along the first direction DR1 on the first support portion SUP1, and the inkjet head IH can move to a specific position to eject ink onto the target substrate SUB.

[0051] The print head unit HU can move in a first direction DR1 in which the first support portion SUP1 extends, and the inkjet head IH can move in the first direction DR1 and eject ink onto the target substrate SUB.

[0052] In an exemplary embodiment, the ink may be provided in a solution or colloid state. For example, the solvent may be acetone, water, ethanol, toluene, propylene glycol (PG), or propylene glycol methyl acetate (PGMA), but is not limited thereto.

[0053] The width of the target substrate SUB measured in the first direction DR1 can be greater than the width of the print head unit HU. In this case, the print head unit HU can move in the first direction DR1 and eject ink all over the target substrate SUB. This specification illustrates a single target substrate SUB positioned on the workstation STA, but this is not limiting; multiple target substrates SUB may be positioned.

[0054] According to one embodiment, a target substrate SUB may include multiple panel areas PA. The multiple panel areas PA may be cut along their edges, and a single target substrate SUB may be separated to form multiple display panels. This specification illustrates an embodiment in which a target substrate SUB includes six panel areas PA, but is not limited thereto.

[0055] According to one embodiment, Figure 3 As shown, each of the plurality of inkjet heads IH may include a plurality of nozzles NZ. Ink may be ejected onto a target substrate SUB through the plurality of nozzles NZ. The inkjet head IH may eject ink through the plurality of nozzles NZ. The ink ejected from the nozzles NZ may be ejected onto a target substrate SUB provided on the worktable STA or the sub-worktable SSTA. The plurality of nozzles NZ may be located on the bottom surface of the inkjet head IH and arranged along a direction in which the inkjet head IH extends.

[0056] When the worktable STA moves in the second direction DR2 and is positioned below the base frame BF, the print head unit HU moves between the first and second guide rails RL1 and RL2 and ejects ink via the inkjet head IH. The operation of the inkjet head IH is not limited to this and can be modified in various ways within the scope of this embodiment. A detailed description of the operation of the inkjet head IH will be omitted.

[0057] The work stage STA can include a plate-shaped portion that can secure the target substrate SUB and guide rails RL1 and RL2 that can move it. The work stage STA includes two guide rails RL1 and RL2, and can use the guide rails RL1 and RL2 to move the target substrate SUB in a second direction DR2 or other direction. The target substrate SUB is the target for inkjet printing. The work stage STA can move the target substrate SUB while simultaneously spraying ink onto the entire surface of the target substrate SUB to form a predetermined layer. For example, an organic light-emitting layer can be formed on the target substrate SUB.

[0058] Meanwhile, this specification describes an embodiment in which the position of ink ejected from the inkjet head IH is adjusted by moving the print head unit HU in the first direction DR1 and the stage STA in the second direction DR2, but the present invention is not limited thereto. Specifically, the position of ink ejection may be adjusted by moving the print head unit HU in both the first and second directions DR1 and DR2, or the position of ink ejection may be adjusted by moving the stage STA in both the first and second directions DR1 and DR2.

[0059] The sub-stage SSTA can provide a space for configuring the object substrate SUB. In addition, the substrate rotation unit RL can be configured on the sub-stage SSTA. The shape of the sub-stage SSTA is not particularly limited, but as an example, as shown in the figure, the sub-stage SSTA can have a quadrilateral shape with two sides extending in the first direction DR1 and the second direction DR2. The sub-stage SSTA may include a long side extending in the first direction DR1 and a short side extending in the second direction DR2. However, the overall planar shape of the sub-stage SSTA may be changed according to the planar shape of the object substrate SUB. For example, when the object substrate SUB is rectangular in plane, as shown in the figure, the shape of the sub-stage SSTA can be rectangular, and when the object substrate SUB has a circular plane, the shape of the sub-stage SSTA in plane can also be circular. This specification shows an embodiment in which the object substrate SUB is configured on the sub-stage SSTA, but is not limited to this. It is also possible that the sub-stage SSTA is omitted and is directly located on the stage STA.

[0060] The substrate rotating units RL may be arranged on the sub-stage SSTA. Alternatively, the substrate rotating units RL may be arranged on each side of the sub-stage SSTA, and the area surrounded by the plurality of substrate rotating units RL is the area where the target substrate SUB is arranged.

[0061] The substrate rotating unit RL may tilt the target substrate SUB in a direction such that one side of the target substrate SUB has a predetermined angle with respect to the first direction DR1 or the second direction DR2.

[0062] This specification shows an embodiment in which an object substrate SUB is arranged on the workbench STA and the substrate rotation unit RL tilts the object substrate SUB, but is not limited to this. It may be that multiple object substrates SUB are arranged on the workbench STA, and the substrate rotation unit RL is tilted so that the multiple object substrates SUB have a predetermined angle relative to the first direction DR1 or the second direction DR2.

[0063] However, in order to tilt the target substrate SUB with respect to the first direction DR1 or the second direction DR2 , the inkjet printing apparatus IP according to one embodiment may also use other components instead of the substrate rotating unit.

[0064] Below, refer to Figures 4 and 5 An inkjet printing method according to one embodiment is described. Figure 4 is a sequence diagram of an inkjet printing method according to an embodiment, Figure 5 FIG1 is a schematic diagram related to a method for manufacturing a display panel using an inkjet printing device according to an embodiment of the present invention. Since the above-mentioned inkjet printing device is used, descriptions of overlapping components will be omitted.

[0065] like Figure 4 As shown, first, a target substrate SUB is loaded on the stage STA or the sub-stage SSTA ( S100 ). The target substrate SUB may be placed on the stage STA or the sub-stage SSTA.

[0066] During the inkjet printing process, the work stage STA may move along the second direction DR2, but the present invention is not limited thereto, and the moving direction of the work stage STA may be changed in various ways.

[0067] Next, the substrate rotating unit RL is used to adjust the position of the target substrate SUB ( S200 ). Specifically, the substrate rotating unit RL may be used to tilt the target substrate SUB so that one side thereof has a predetermined angle relative to the first direction DR1 or the second direction DR2 .

[0068] Next, the print head unit HU is positioned on the target substrate SUB and ink is ejected onto the target substrate SUB (S300). At this time, the print head unit HU can be positioned above one side edge of the target substrate SUB. The print head unit HU can eject ink while moving along the second direction DR2 from one side edge.

[0069] Below, refer to Figure 5 According to one embodiment, the target substrate SUB disposed on the stage STA or the sub-stage SSTA may be tilted so that the first side E1 of the target substrate SUB has a predetermined angle θ with respect to the second direction DR2. The second direction DR2 may be the moving direction of the inkjet head IH.

[0070] The inkjet head IH may be disposed on the target substrate SUB, and the inkjet head IH may eject ink onto the plurality of pixel regions PX included in the target substrate SUB while moving in the second direction DR2.

[0071] Based on a process in which the inkjet head IH moves once in the second direction DR2 , the plurality of nozzles NZ may include nozzles a for ejecting ink in the ejection process and unused nozzles b.

[0072] According to one embodiment, the first nozzle group NZ1 may be used for a plurality of pixel regions PX arranged along a column direction. This specification shows an embodiment in which one first nozzle group NZ1 includes four nozzles NZ, but the number is not limited to this.

[0073] The width W4 occupied by the first nozzle group NZ1 can be greater than the width W3 of a single pixel region PX. Specifically, the width W4 occupied by the first nozzle group NZ1 can be equal to or slightly less than the distance between a virtual first line L1 extending from a first vertex P1 and a virtual second line L2 extending from a second vertex P2 of a plurality of pixel regions PX located in the same column. Compared to a state where the target substrate SUB is not tilted, the width occupied by the first nozzle group NZ1 can be increased. Therefore, the number of nozzles a used to eject ink to form the pixel regions PX can be increased.

[0074] This specification includes diagrams showing an unused nozzle b between the first nozzle groups NZ1, but is not limited to this embodiment. Alternatively, the first nozzle groups NZ1 may be arranged continuously, with no individual nozzles arranged between them. However, this is not limiting. Alternatively, multiple first nozzle groups NZ1 may be arranged continuously, with one or more unused nozzles NZ arranged between them.

[0075] The number of nozzles NZ included in the first nozzle group NZ1 when the target substrate SUB is tilted at the predetermined angle θ can be greater than the number of nozzles NZ included in the first nozzle group NZ1 when the target substrate SUB is not tilted. Based on a process in which the inkjet head IH moves once in the second direction DR2, a larger number of nozzles NZ can be used.

[0076] At this time, the angle θ at which the target substrate SUB is tilted will be described.

[0077] The first side E1 of the target substrate SUB may have an inclination with respect to the second direction DR2 that is equal to or smaller than a first angle (θ1). The first angle (θ1) may be derived from the following formula 1.

[0078] θ1=tan -1 (W2 / W1)(Formula 1)

[0079] In the above formula 1, W1 is the length W1 of the first side E1 of the target substrate SUB, and W2 is the width W2 of the inkjet head IH.

[0080] When the first side E1 of the target substrate SUB is tilted so as to have an inclination greater than the first angle (θ1) relative to the second direction DR2, the number of times the inkjet head IH moves along the second direction DR2 may increase, or the number of inkjet heads IH required to be included in the inkjet printing apparatus may increase. Consequently, the time and cost required for the process increase, and an efficient inkjet printing process may be difficult to provide.

[0081] For example, the width W2 of the inkjet head IH may be approximately 50 mm, and the length W1 of the first side E1 of the target substrate SUB along the second direction DR2 may be approximately 2500 mm. In this case, the first angle (θ1) may be approximately 1.14576 degrees.

[0082] The first side E1 of the target substrate SUB may have an inclination greater than or equal to a second angle (θ2) with respect to the second direction DR2. The second angle (θ2) may be derived from the following formula 2.

[0083] θ2=tan -1 (1 / the number of pixel regions arranged along the second direction based on one column arranged in one panel region) (Formula 2)

[0084] When the first side E1 of the target substrate SUB is tilted so as to have an inclination smaller than the second angle (θ2) with respect to the second direction DR2, the number of nozzles NZ included in the first nozzle group NZ1 may be almost unchanged compared to a case where the target substrate SUB is not tilted. Therefore, since the number of nozzles NZ used in the inkjet printing process is small, the reliability of the inkjet printing process may be low.

[0085] According to one embodiment, when the number of pixel regions PX arranged along the second direction DR2 is 1000, based on one panel area PA included in one target substrate SUB, the second angle (θ2) may be approximately 0.05373 degrees (°). According to one embodiment, when the number of pixel regions PX arranged along the second direction DR2 is 2000, based on one panel area PA included in one target substrate SUB, the second angle (θ2) may be approximately 0.02865 degrees (°). According to one embodiment, when the number of pixel regions PX arranged along the second direction DR2 is 4000, based on one panel area PA included in one target substrate SUB, the second angle (θ2) may be approximately 0.01432 degrees (°). The second angle (θ2) may be 0.01432 degrees (°) to 0.05373 degrees (°), is not limited thereto, and may vary according to the number of pixel regions PX.

[0086] According to one embodiment, the first side E1 of the target substrate SUB may be tilted relative to the second direction DR2 by an angle ranging from less than a first angle (θ1) to greater than a second angle (θ2). According to one embodiment, the first side E1 of the target substrate SUB may be tilted relative to the second direction DR2 by 0.05373 degrees (°) to 1.14576 degrees (°), the first side E1 of the target substrate SUB may be tilted relative to the second direction DR2 by 0.02865 degrees (°) to 1.14576 degrees (°), or the first side E1 of the target substrate SUB may be tilted relative to the second direction DR2 by 0.01432 degrees (°) to 1.14576 degrees (°). However, this is not limited to these and may vary depending on the width of the inkjet head IH, the width of the target substrate SUB, and the number of pixel regions PX arranged along a direction.

[0087] Below, refer to Figure 6 The inkjet printing apparatus and method according to the comparative example are observed. The description of the same components as those described above will be omitted.

[0088] According to the comparative example, the target substrate SUB mounted on the stage may be arranged so that one edge thereof is parallel to the second direction DR2, which is the moving direction of the inkjet head IH.

[0089] Thus, in the process of the inkjet head 1H moving once in the second direction DR2, only the second nozzle group NZ2 can be used. Compared with the above embodiment, the number of nozzles NZ included in the second nozzle group NZ2 can be smaller.

[0090] Therefore, the nozzles used in the inkjet printing process are limited, and nozzles that have not been used for a long time may cause pixel defects by not ejecting ink or abnormally ejecting ink in a process that requires the use of the nozzle.

[0091] The embodiments of the present invention are described in detail above, but the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art using the basic concepts of the present invention defined in the claims also fall within the scope of the present invention.

Claims

1. An inkjet printing device, wherein: include: a workbench for loading a target substrate including a plurality of panel areas; a substrate rotating unit, located on the workbench and configured to tilt the target substrate; as well as an inkjet head, located above the workbench and comprising a plurality of nozzles for ejecting ink, The substrate rotating unit is tilted so that the traveling direction of the inkjet head and the first side of the target substrate form an angle smaller than a first angle. The first angle is derived from the following formula 1: θ1=tan -1 (W2 / W1) Formula 1, In the above formula (1), θ1 is the first angle, W1 is the length of the first side of the target substrate, and W2 is the width of the inkjet head.

2. The inkjet printing device according to claim 1, wherein When the target substrate is not tilted, the first side is parallel to the moving direction of the inkjet head.

3. The inkjet printing device according to claim 1, wherein The first side has an inclination greater than a second angle with respect to the second direction, which is the traveling direction of the inkjet head. The second angle is derived from the following formula 2: θ2=tan -1 (1 / the number of pixel regions arranged along the second direction based on one column included in one panel region) Formula 2, In the above formula 2, θ2 is the second angle.

4. The inkjet printing device according to claim 1, wherein The nozzles include a first nozzle group that ejects ink in a process in which the inkjet head moves once in a traveling direction.

5. The inkjet printing device according to claim 4, wherein The width occupied by the first nozzle group is greater than the width of one pixel area.

6. The inkjet printing device according to claim 5, wherein: The width occupied by the first nozzle group is equal to or smaller than a distance between a virtual first line formed by first vertices and a virtual second line formed by second vertices of a plurality of pixel regions located in the same column.

7. An inkjet printing method, wherein: include: a step of placing a target substrate including a plurality of panel areas on a workbench; The step of tilting the target substrate at a first angle or less; as well as The step of disposing an inkjet head on the target substrate and ejecting ink through a plurality of nozzles, The first angle is an angle formed by the traveling direction of the inkjet head and the first side of the inclined target substrate. The first angle is derived from the following formula 1: θ1=tan -1 (W2 / W1) Formula 1, In the above formula (1), θ1 is the first angle, W1 is the length of the first side of the target substrate, and W2 is the width of the inkjet head.

8. The inkjet printing method according to claim 7, wherein: When the target substrate is tilted, the first side has an inclination greater than a second angle with respect to a second direction that is a moving direction of the inkjet head. The second angle is derived from the following formula 2: θ2=tan -1 (1 / the number of pixel regions arranged along the second direction based on one column included in one panel region) Formula 2, In the above formula 2, θ2 is the second angle.

9. The inkjet printing method according to claim 8, wherein: The number of pixel regions arranged along the second direction based on one panel region among the plurality of panel regions is 1000 to 4000.

10. The inkjet printing method according to claim 9, wherein: In the process of the inkjet head moving once along the second direction, the plurality of nozzles include a first nozzle group for ejecting ink, The width occupied by the first nozzle group is greater than the width of one pixel area.

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