Printing method, color filter manufacturing method and printing device

Abstract

The invention provides a printing method, a color filter manufacturing method and a printing device. The printing method includes: a printing path calculation step of calculating at least one printing path to be applied when printing of a substrate is performed; and a printing step of performing printing of the substrate by applying the printing path calculated in the printing path calculation step, in which a color filter layer and a columnar spacer higher than the color filter layer are simultaneously formed on the substrate in the printing step.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0110903, filed on August 20, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a printing method, a method for manufacturing color filters, and a printing apparatus. Background Technology

[0004] In display manufacturing, inkjet printers, which eject ink in droplet form, are widely used. These printers can precisely deliver the required amount of ink to the desired locations on substrates such as glass, making them highly effective in display manufacturing. This method is an indispensable technology for achieving high-resolution displays, and is particularly suitable for manufacturing LCD and OLED displays.

[0005] Figure 1 This is a diagram illustrating the columnar spacers used in the bonding process of thin-film transistors (TFTs) and color filters.

[0006] Reference Figure 1 A black matrix BM is formed on a substrate G, and RGB ink I is sprayed between the black matrix to form a color filter layer. The black matrix BM refers to the black area in the display that distinguishes the red, green, and blue (RGB) sub-pixels. Typically, before the formation of the RGB color filter layer, the black matrix BM serves as a separating structure to distinguish each sub-pixel area. Furthermore, it prevents backlight leakage from the LCD, prevents color mixing between RGB sub-pixels, and prevents increased TFT leakage current caused by external light sources. The RGB color filter layer is formed by spraying a target volume of RGB ink I into the sub-pixels distinguished by the black matrix BM.

[0007] The black matrix BM is formed using photolithography. Additionally, an overcoat layer COT1 is formed on the RGB color filter to level out height unevenness in the color filter layer. A transparent electrode (indium tin oxide (ITO)) COT2 is formed on the topmost layer in thin film form to enable driving the liquid crystal after subsequent bonding with the TFT substrate. The color filter includes a substrate G, a black matrix BM, an RGB color filter layer, an overcoat layer COT1, and a transparent electrode COT2.

[0008] In addition, the manufacturing process of the display includes the aforementioned bonding process between the color filter and the TFT. After bonding, the panel is cut into a size that matches the screen of a TV or mobile device through a scribe process, then liquid crystal is injected and the final step, the module process, is completed to obtain the display panel.

[0009] In the bonding process, it is important to avoid the TFT and color filter being completely flush during bonding. This is because if the bonding time between the TFT and the color filter is too close, there will be insufficient space to fill the liquid crystal. To solve this problem, columnar spacers (CS) are formed in the final step of color filter manufacturing. During the bonding of the TFT and the color filter, the columnar spacers ensure sufficient space between the two substrates. However, this method has the drawback that an additional photolithography process is required to form the columnar spacers (CS). Summary of the Invention

[0010] (a) Technical problems to be solved

[0011] The purpose of this invention is to provide a printing method, a color filter manufacturing method, and a printing apparatus that can effectively process substrates.

[0012] In addition, the present invention aims to provide a printing method, a color filter manufacturing method, and a printing apparatus that can minimize the time required to manufacture color filters.

[0013] In addition, the present invention aims to provide a printing method, a color filter manufacturing method, and a printing apparatus that can eliminate the need for additional photolithography processes required to manufacture columnar spacers.

[0014] Furthermore, according to embodiments of the present invention, forming both RGB color filters and columnar spacers simultaneously during the printing step minimizes the increase in the number of printing paths.

[0015] (II) Technical Solution

[0016] The present invention provides a printing method, the method comprising: a printing path calculation step of calculating at least one printing path to be applied when printing on a substrate; and a printing step of applying the printing path calculated in the printing path calculation step to perform printing on the substrate, wherein a color filter layer and columnar spacers with a height higher than the color filter layer are simultaneously formed on the substrate.

[0017] According to one embodiment, the printing path calculation step may include: step a, determining whether applying a set number of printing paths to the printing step satisfies a first target volume for forming the color filter layer; step b, when the set number of printing paths satisfies the first target volume, determining whether a second target volume can be used to fill a target number or more of the spacer pixels forming the columnar spacers, wherein step b is performed after step a.

[0018] According to one embodiment, in step b, it is determined whether the amount of ink ejected by the printhead unit in step a, which maintains the set number of printing paths but increases to form the color filter layer, is sufficient to fill more than the target number.

[0019] According to one embodiment, when the first target volume cannot be filled in step a, or when the second target volume cannot be filled with more than the target number of spacer pixels in step b, the set number can be increased, and step a can be executed.

[0020] According to one embodiment, the spacer pixels selected in step b may be randomly selected, and a selection probability distribution for selecting the spacer pixels is uniformly set throughout the entire area of ​​the substrate.

[0021] According to one embodiment, the ink sprayed onto the substrate in the printing step may include a variety of types, at least one of the inks including a light-emitting element, and at least one of the inks not including the light-emitting element.

[0022] According to one embodiment, the ink used to form the columnar spacers may be of a type that does not include the light-emitting element.

[0023] According to one embodiment, the ink used to form the color filter layer may include red ink, green ink, and blue ink, the ink used to form the columnar spacers is composed of blue ink, the red ink and the green ink include the light-emitting element, and the blue ink does not include the light-emitting element.

[0024] In addition, the present invention provides a manufacturing method. The manufacturing method may include a printing step of simultaneously printing a color filter layer and columnar spacers with a height higher than the color filter layer by jetting ink onto a substrate forming a black matrix.

[0025] According to one embodiment, the method may include: a first coating step of forming a cover layer on the substrate after forming the color filter layer and the columnar spacers; and a second coating step of forming a transparent electrode in the form of a thin film on the upper part of the cover layer after the first coating step.

[0026] According to one embodiment, the upper end of the columnar spacer formed in the printing step may be located above the upper surface of the transparent electrode.

[0027] According to one embodiment, the method may further include a printing path calculation step of calculating at least one printing path applied when printing the substrate, wherein in the printing step, the printhead unit that ejects the ink applies the printing path calculated in the printing path calculation step to print the color filter layer and the columnar spacers.

[0028] According to one embodiment, the printing path calculation step may include: step a, determining whether applying a set number of printing paths to the printing step satisfies a first target volume for forming the color filter layer; and step b, when the set number of printing paths satisfies the first target volume, determining whether a target number or more spacer pixels forming the columnar spacers can be filled with a second target volume, wherein step b is performed after step a.

[0029] According to one embodiment, in step b, it is determined whether the amount of ink ejected by the printhead unit in step a, which maintains the set number of printing paths but increases to form the color filter layer, is sufficient to fill more than the target number.

[0030] According to one embodiment, when the first target volume cannot be filled in step a, or when the second target volume cannot be filled with more than the target number of spacer pixels in step b, the set number can be increased, and step a can be executed.

[0031] According to one embodiment, the spacer pixels selected in step b may be randomly selected, and a selection probability distribution for selecting the spacer pixels is uniformly set throughout the entire area of ​​the substrate.

[0032] According to one embodiment, the ink used to form the color filter layer may include red ink, green ink, and blue ink, the ink used to form the columnar spacers is composed of blue ink, the red ink and the green ink include the light-emitting element, and the blue ink does not include the light-emitting element.

[0033] Additionally, the present invention provides a printing apparatus, which may include: a printing table; a transport unit for transporting a substrate on the printing table; a nozzle unit for spraying ink onto the substrate; and a controller for controlling at least one of the transport unit, the nozzle unit, and the printing table. The controller may be configured to calculate a printing path to be applied when printing the substrate, and to perform the basic printing according to the calculated printing path. During the printing process, the nozzle unit and the transport unit are controlled to spray the ink onto sub-pixels and spacer pixels, the sub-pixels being used to form a color filter layer on the substrate, and the spacer pixels being used to form columnar spacers.

[0034] According to one embodiment, the controller may be configured to calculate the number of printing paths that satisfy a first target volume to be sprayed onto the sub-pixel, calculate the number of spacer pixels that the printhead unit can fill based on the calculated printing paths, and determine whether the calculated number of spacer pixels is greater than or equal to the target number. When the calculated number of spacer pixels is greater than or equal to the target number, the controller controls the printhead unit and the transport unit to perform the printing using the calculated printing paths.

[0035] According to one embodiment, the printhead unit may be configured to eject at least one of the ink including a light-emitting element and the ink excluding the light-emitting element, and the controller is configured to control the printhead unit to eject the ink excluding the light-emitting element to the spacer pixel.

[0036] (III) Beneficial Effects

[0037] According to one embodiment of the present invention, the substrate can be effectively processed.

[0038] Furthermore, according to one embodiment of the present invention, the time required to manufacture the color filter can be minimized.

[0039] In addition, according to one embodiment of the present invention, the additional photolithography process required to manufacture columnar spacers can be omitted.

[0040] In addition, according to one embodiment of the present invention, in the printing step, RGB color filters and columnar spacers are formed simultaneously, which can minimize the increase in the number of printing paths.

[0041] The effects of the present invention are not limited to those described above. Those skilled in the art will clearly understand the effects not described above through this specification and the accompanying drawings. Attached Figure Description

[0042] Figure 1 This is a diagram illustrating the columnar spacers used in the bonding process of bonding TFTs and color filters.

[0043] Figure 2 This is a diagram illustrating a printing apparatus according to an embodiment of the present invention.

[0044] Figure 3 Watch below Figure 2 A diagram of a nozzle plate with a nozzle.

[0045] Figure 4 This is a flowchart illustrating a printing method according to an embodiment of the present invention.

[0046] Figure 5Is to show execution Figure 4 A diagram of the printing apparatus used in the testing process.

[0047] Figure 6 and Figure 7 Is to show execution Figure 4 A diagram of a printing apparatus used in the printing process.

[0048] Figure 8 This diagram illustrates the pixels that should be sprayed with ink when forming an RGB color filter layer and columnar spacers on a substrate.

[0049] Figure 9 It is applied to Figure 4 The flowchart shows the algorithm in the printing path calculation step.

[0050] Figure 10 It is an illustration of using through Figure 9 The algorithm calculates a planar diagram of the RGB color filter layer and columnar spacers formed by the printing path.

[0051] Figure 11 It is an illustration of using through Figure 9 The algorithm calculates the cross-sectional view of the RGB color filter layer and columnar spacers formed by the printing path.

[0052] Figure 12 This is a flowchart illustrating a substrate processing method according to an embodiment of the present invention.

[0053] Explanation of reference numerals in the attached figures

[0054] 1: Printing apparatus; 10: Printing section

[0055] 11: Printing table 12: Conveyor fixture

[0056] 20: Maintenance Department 21: Maintenance Station

[0057] 22: Conveyor plate; 30: Gantry.

[0058] 40: Nozzle unit; 41: Housing

[0059] 42: Spray nozzle 43: Visual inspection section

[0060] 50: Controller; 60: Test Unit

[0061] S1: Test Steps S2: Printing Path Calculation Steps

[0062] S3: Printing step; S4: First coating step

[0063] S5: Second coating step; S6: Bonding step Detailed Implementation

[0064] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings to enable those skilled in the art to readily implement the invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Furthermore, in describing preferred embodiments of the invention in detail, detailed descriptions of relevant well-known functions or structures are omitted if it is deemed unnecessary to obscure the spirit of the invention. Additionally, the same reference numerals are used in all the drawings for parts with similar functions and effects.

[0065] When describing a component as "comprising" other components, unless specifically stated otherwise, the inclusion of other components is not excluded, indicating that further inclusion of other components is possible. Specifically, terms such as "comprising" or "having" in the specification are used to specify the presence of the described features, numbers, steps, actions, components, parts, or combinations thereof, without pre-excluding the presence or additional possibilities of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0066] Unless explicitly stated in the context, singular expressions include plural forms. Furthermore, for greater clarity, the shapes and dimensions of elements in the accompanying drawings may be enlarged.

[0067] Terms such as "first" and "second" can be used to describe various constituent elements, but these constituent elements should not be limited by these terms. These terms are used to distinguish one constituent element from another. For example, without departing from the scope of the invention, a first constituent element may be named a second constituent element, and similarly, a second constituent element may be named a first constituent element.

[0068] When describing a component as "connected" or "linked" to other components, it should be understood as being directly connected or linked to those other components, although other components may exist in between. Conversely, when describing a component as "directly connected" or "directly linked" to other components, it should be understood as meaning that no other components exist in between. Other expressions used to describe the relationship between components, such as "between ~" and "directly between ~", or "adjacent to ~" and "directly adjacent to ~", should also be interpreted similarly.

[0069] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries shall be interpreted as having the same meaning as those in the relevant technical documents, and shall not be construed as having an idealized or overly formal meaning unless expressly defined in this application.

[0070] Below, refer to Figures 2 to 12The embodiments of the present invention will be described in detail below.

[0071] Figure 2 This is a diagram illustrating a printing apparatus according to an embodiment of the present invention.

[0072] Reference Figure 2 In one embodiment of the present invention, the printing apparatus 1 can jet ink I onto a substrate G. The printing apparatus 1 can jet red ink I (R), green ink I (G), and blue ink I (B) onto the substrate G. The printing apparatus 1 can also jet RGB ink onto the substrate G and form an RGB color filter layer on the substrate G. Furthermore, the printing apparatus 1 can jet ink I onto the substrate G to form column spacers (CS) on the substrate G. The printing apparatus 1 can be an inkjet device. The substrate G can be a glass substrate.

[0073] The printing apparatus 1 may include a printing unit 10, a maintenance unit 20, a gantry 30, a printhead unit 40, a controller 50, and a testing unit 60.

[0074] The printing section 10 can be the area where printing is performed on the substrate G. The printing section 10 can include a printing table 11 and a transport fixture 12 (an example of a transport unit). The substrate G can be loaded and / or unloaded on the printing table 11. The printing table 11 can spray air onto the lower surface of the substrate G, causing the substrate G to float. When the lower surface of the substrate G is in direct contact with the printing table 11, impurities such as particles may be present due to the contact. These impurities adhere to the upper surface of the substrate G, causing a decrease in the quality of the manufactured display panel. To solve this problem, the printing table 11 sprays air onto the lower surface of the substrate G, thus separating the lower surface of the substrate G from the printing table 11.

[0075] The suspended substrate G can be held by the transport clamp 12. The transport clamp 12 can hold one side of the substrate G (or both sides if needed). The transport clamp 12 can hold the lower part of the edge region of the substrate G by vacuum adsorption. The transport clamp 12 can be configured to move along the second direction Y. The transport clamp 12 can hold one side of the suspended substrate G and move the substrate G along the second direction Y while simultaneously moving the substrate G along the second direction Y.

[0076] Below, the direction of the conveying base plate G of the conveying fixture 12 can be defined as the second direction Y. When viewed from above, the direction perpendicular to the second direction Y is defined as the first direction X, and the direction perpendicular to the first direction X and the second direction Y is defined as the third direction Z. The third direction Z can represent the direction perpendicular to the ground.

[0077] The maintenance unit 20 can be arranged side-by-side with respect to the printing unit 10 along the first direction X. The maintenance unit 20 can perform maintenance operations such as inspection, test spraying, cleaning spraying, cleaning, replacement, and repair on the printhead unit 40, which will be described later. The maintenance unit 20 can generally have a similar structure and environment to the printing unit 10. For example, the printing unit 10 and the maintenance unit 20 can be housed in the same sealed cavity. The sealed cavity can be filled with an inert gas such as nitrogen. That is, both the printing unit 10 and the maintenance unit 20 can be controlled in an inert gas atmosphere. As described above, the printing unit 10 and the maintenance unit 20 are controlled in the same or similar process environment because the maintenance unit 20 may perform operations such as test spraying to test the performance of the printhead unit 40.

[0078] The maintenance unit 20 may include a maintenance table 21 and a conveyor plate 22. The maintenance table 21 has the same or similar shape and function as the printing table 11 described above, and the conveyor plate 22 is configured to move on the maintenance table 21.

[0079] The conveyor plate 22 can be configured to move along the second direction Y and / or the first direction X on the maintenance table 21. The conveyor plate 22 may have a placement surface capable of placing the test unit 60. The conveyor plate 22 can be moved along the first direction X and / or the second direction Y by an actuator such as a motor (not shown). When the nozzle unit 40 is located above the maintenance section 20 for performing test spraying, the conveyor plate 22 can position the test unit 60 below the nozzle unit 40.

[0080] The gantry 30 may have a vertical extension extending in a vertical direction and a horizontal extension extending in a horizontal direction. The vertical extension may be located on the side of the printing table 11 of the printing unit 10 and the side of the maintenance table 21 of the maintenance unit 20, respectively. Furthermore, the horizontal extension may be located on the upper part of the printing table 11 and the maintenance unit 20. The horizontal extension may extend in a first direction X.

[0081] Furthermore, the gantry 30 may have a moving mechanism capable of moving the printhead unit 40. For example, the moving mechanism of the gantry 30 may consist of a motor, a guide rail, and a moving bracket that moves along the guide rail. The printhead unit 40 can move along the first direction X via this moving mechanism. The printhead unit 40 can move between the printing section 10 and the maintenance section 20 via the gantry 30. When the printhead unit 40 is located above the printing section 10, a printing process can be performed on the substrate G. When the printhead unit 40 is located above the maintenance section 20, maintenance operations such as inspection, test spraying, cleaning spraying, cleaning, replacement, and repair can be performed on the printhead unit 40.

[0082] The printhead unit 40 can jet ink I onto the substrate G. The printhead unit 40 is capable of jetting ink I onto the substrate G in droplet form. The printhead unit 40 can jet ink I onto the substrate G to form an RGB color filter layer on the substrate G. Furthermore, the printhead unit 40 can jet ink I onto the substrate G to form columnar spacers CS on the substrate G.

[0083] Additionally, at least a portion of the ink I ejected by the printhead unit 40 may include a light-emitting element referred to as a nanorod LED. For example, in the ink I ejected by the printhead unit 40, the red ink I (R) and the green ink I (G) may include light-emitting elements. The light-emitting elements may have nanoscale dimensions. The light-emitting elements may have a cylindrical structure. The light-emitting elements are contained within the ink I, and when an electric field is applied to the RGB color filter, the light-emitting elements can automatically align and align under the influence of the electric field.

[0084] The nozzle unit 40 may include a housing 41, a plurality of nozzles 42, and a vision unit 43.

[0085] The housing 41 can be combined with a moving mechanism of the gantry 30. The housing 41 can be a main component for inserting and fixing the nozzles 42. Multiple nozzles 42 can be inserted and fixed into the housing 41. Figure 3 As shown, each of the plurality of printheads 42 may have a nozzle plate NP. Multiple nozzles N are formed in each nozzle plate NP. Each nozzle N can eject ink I in droplet form. Each printhead 42 has a droplet ejection device such as a piezoelectric element to adjust the volume of a unit of ink I in droplet form. The volume of ink I ejected onto the substrate G can be adjusted by the current intensity applied to the piezoelectric element and the duration of current application to the piezoelectric element.

[0086] Figure 3 The example shown has 24 nozzles N formed in a nozzle plate NP, but it is not limited to this. For example, the number of nozzles N formed in each nozzle plate NP can be tens to thousands, and varies greatly.

[0087] Re-reference Figure 2 The vision unit 43 can be provided on the side of the housing 41. The vision unit 43 can be a camera including illumination. The vision unit 43 can acquire images of ink I sprayed onto the substrate G. The ink I sprayed onto the substrate G refers to ink I in droplet form that has adhered to the surface of the substrate G or is in the process of falling to adhere to the surface of the substrate G. The vision unit 43 can acquire images that can confirm the spraying position of the droplet-shaped ink I on the substrate G, the volume of the sprayed ink I, etc. Furthermore, the vision unit 43 can acquire relevant images of ink I sprayed onto the test unit 60 described later. Thus, the controller 50 described later can determine which nozzle N of the nozzles N provided in the printhead unit 40 is a defective nozzle DN.

[0088] The controller 50 can control the operation of the printing apparatus 1. The controller 50 can generate control signals to control the operation of the printing apparatus 1. The controller 50 may include: a process controller, consisting of a microprocessor (computer) for controlling the printing apparatus 1; a user interface, for operator management of the printing apparatus 1, consisting of a keyboard or display, the keyboard for command input, the display for visually displaying the driving status of the printing apparatus 1; and a storage unit storing a control program or program that causes the printing apparatus 1 to perform processes under the control of the process controller, the program causing each component to process according to various data and processing conditions. Additionally, the controller 50 may have a storage medium storing a program for enabling the printing apparatus 1 to perform the printing method described later. The storage medium may be a hard disk, a removable disk such as a CD-ROM / DVD, or a semiconductor memory such as flash memory.

[0089] The test unit 60 can be installed in the maintenance unit 20. The test unit 60 can provide a test component. The test component can be a test film or a test substrate, etc., that enables the printhead unit 40 to perform test spraying. For example, the test unit 60 can be configured to be unwound and rewound in a roll-to-roll manner. When the printhead unit 40 is located above the test unit 60, the printhead unit 40 sprays ink I in droplet form onto the test component provided by the test unit 60. In addition, the state of the nozzle N provided by the printhead unit 40 can be evaluated by whether the ink I sprayed onto the test component adheres, the adhesion location, the adhesion volume, etc.

[0090] Figure 4 This is a flowchart illustrating a printing method according to an embodiment of the present invention. The printing method according to an embodiment of the present invention can be part of a method for manufacturing a color filter. The color filter can be a partial structure of the manufactured display panel. The color filter can be a structure that undergoes a bonding process with a TFT substrate. The printing method can include a testing step S1, a printing path calculation step S2, and a printing step S3. The testing step S1, the printing path calculation step S2, and the printing step S3 can be performed sequentially.

[0091] Figure 5 Is to show execution Figure 4 A diagram of the printing apparatus for the testing steps.

[0092] Reference Figure 4 and Figure 5In test step S1, the printhead unit 40 can be moved along the first direction X via the moving mechanism in the gantry 30 and positioned above the maintenance section 20. Then, the conveyor plate 22 can move the test unit 60 below the printhead unit 40. In this step, the printhead unit 40 can spray test ink I into the test unit 60 in droplet form. The test unit 60 provides a test component, which can be composed of a test film that is unwound and rewound in a roll-to-roll manner. Ink I can adhere to the test component.

[0093] During testing, the vision unit 43 captures images of the ink I adhering to the test component. These images are analyzed by the controller 50 to evaluate the condition of the nozzles N included in the printhead unit 40. The condition of the nozzles N can be graded according to specific criteria and managed by the controller 50.

[0094] For example, among the nozzles N, those with excellent performance in all indicators such as ink I adhesion, adhesion location, and adhesion volume can be classified as Grade A. Two nozzles with excellent indicators can be classified as Grade B, one nozzle with excellent indicators as Grade C, and all nozzles with poor performance in all indicators as Grade D. This classification system allows for systematic monitoring of the nozzle N's condition and is an important factor in maintaining optimal print quality in subsequent printing processes. However, this classification is just an example, and classification criteria can be diversified and varied.

[0095] The grade of nozzle N can be considered when selecting the nozzle N that actually participates in printing on the substrate G in the printing path calculation step S2 and printing step S3 described later. For example, when the printhead unit 40 performs printing on the substrate G along the first printing path, a nozzle N with a higher grade can be preferentially selected from the nozzles N that can participate in printing on the first printing path. Similarly, when the printhead unit 40 performs printing on the substrate G along the second printing path, a nozzle N with a higher grade can be preferentially selected from the nozzles N that can participate in printing on the second printing path. This optimizes printing quality and minimizes defective printing.

[0096] The printing path calculation step S2 can be executed after the test step S1 is completed. The printing path calculation step S2 can calculate the position, number, and application order of the printing path that can meet the user-set request conditions when the printhead unit 40 performs printing on the substrate G.

[0097] The specific details of the calculation algorithm used to perform the printing path calculation step S2 will be described later.

[0098] After completing the printing path calculation step S2, the printing path calculated in the printing path calculation step S2 is used to execute the printing step S3 of the substrate G.

[0099] Figure 6 and Figure 7 Is to show execution Figure 4 A diagram of a printing apparatus used in the printing process. Figure 6 The diagram shows the printing apparatus 1 performing printing on substrate G according to the first printing path. Figure 7 The diagram shows the printing apparatus 1 performing printing of substrate G according to the second printing path.

[0100] Reference Figure 4 , Figure 6 and Figure 7 In the printing step S3 of the present invention, the printing of the substrate G can be performed through at least one printing path. For example, the printing step S3 can perform multiple unit printings through multiple printing paths.

[0101] Printing step S3 is a step in which the substrate G is printed according to the printing path calculated in printing path calculation step S2. This printing step S3 can be performed in printing section 10, and during printing step S3, the printhead unit 40 can be located above printing section 10.

[0102] In printing step S3, when the printhead unit 40 performs printing through the first printing path, the printhead unit 40 can be located at the first printing position. At this time, the substrate G can pass through the area below the printhead unit 40 located at the first printing position, and the substrate G can be transported by the transport jig 12. When the substrate G passes through the area below the printhead unit 40, the nozzle N of the printhead unit 40 can spray ink I onto the substrate G.

[0103] During this process, the controller 50 can control the printhead unit 40, prioritizing the participation of higher-grade nozzles N among the nozzles N that can participate in printing on the first printing path. This optimizes print quality and minimizes defective prints.

[0104] Subsequently, when the printhead unit 40 performs printing through the second printing path, the printhead unit 40 can be located at the second printing position. The second printing position may be different from the first printing position, and in this second printing position, the substrate G can also pass through the area below the printhead unit 40. At this time, the substrate G is also transported by the transport fixture 12, and when the substrate G passes through the area below the printhead unit 40, the nozzles N of the printhead unit 40 eject ink I. The controller 50 can also control the printhead unit 40 so that the higher-level nozzles N among the nozzles N that can participate in printing through the second printing path participate in printing first.

[0105] Furthermore, the substrate G transport direction during the printing of the first printing path can be opposite to the substrate G transport direction during the printing of the second printing path. For example, if the substrate G is transported forward along the second direction Y during the printing of the first printing path, then the substrate G can be transported backward along the second direction Y during the printing of the second printing path. This method is designed to form the desired pattern on the substrate G through multiple printing paths, thereby improving the flexibility and accuracy of the printing process.

[0106] Figure 8 This diagram illustrates the pixels that should be sprayed with ink when forming an RGB color filter layer and columnar spacers on a substrate.

[0107] Figure 8 In this diagram, the blocks denoted by "R", "G", and "B" refer to the sub-pixels on which red ink I (R), green ink I (G), and blue ink I (B) are ejected, respectively. The block denoted by "CS" refers to the spacer pixels on which ink I used to form columnar spacers CS is ejected. Furthermore, the size of the spacer pixels used to form the columnar spacers CS can be smaller than the size of the sub-pixels used to form the RGB color filter. This is because the height of the columnar spacers CS should be greater than the height of the RGB color filter layer.

[0108] A black matrix BM can be formed on the substrate G. The black matrix BM is a crucial component of the display panel, serving to divide sub-pixels and prevent interference between them. Typically, the black matrix BM consists of black areas, playing a vital role in preventing light leakage between RGB sub-pixels and improving image quality in LCD displays. Furthermore, it minimizes reflections caused by external light and internal electrical interference, thereby contributing to improved contrast and color gamut. Moreover, the black matrix BM not only divides sub-pixels but also serves to divide the aforementioned spacer pixels.

[0109] The black matrix BM can be formed by photolithography before the substrate G is transported to the inkjet device 1. In this process, the black matrix BM is formed in a manner that divides the substrate G into sub-pixels and spacer pixels. The sub-pixels and spacer pixels formed in this way can provide space for forming the RGB color filter layer and the columnar spacers CS, respectively, and play a key role in maintaining the high resolution and clarity of the display.

[0110] A subpixel is the basic pixel unit of a display, and each subpixel is used to represent a color in the display. Red (R), green (G), and blue (B) subpixels combine to form a complete pixel, thereby enabling a variety of colors. In the subpixels divided by the black matrix BM, red ink I (R), green ink I (G), and blue ink I (B) can be ejected respectively, thereby forming an RGB color filter layer on the substrate G.

[0111] Furthermore, in the printing step S3 of this invention, ink I can be simultaneously ejected not only onto the RGB color filter layer but also onto the sub-pixels used to form the columnar spacers CS, i.e., the spacer pixels. The columnar spacers CS are an important element in maintaining the required spacing when bonding the TFT and the color filter, and help ensure the physical stability of the display panel and the uniform distribution of liquid crystal during the bonding process.

[0112] Figure 9 It is applied to Figure 4 The flowchart shows the algorithm in the printing path calculation step. Figure 10 It is an illustration of using through Figure 9 The algorithm calculates a planar diagram of the RGB color filter layer and columnar spacers formed by the printing path.

[0113] Reference Figure 9 and Figure 10 The printing path calculation step S2 can be implemented by a program stored in the storage medium of the controller 50. This program is an important software element designed to optimize the printing path to be applied in the printing step S3, and may include algorithms that can calculate the number of printing paths, the position of the printing paths, the application order of the printing paths, etc.

[0114] This program can be implemented by computer software and can consider various variables and conditions to calculate the printing path. For example, the program can generate the optimal printing path by analyzing the complexity of the pattern to be formed on the substrate G, the speed of the inkjet device, the state of the nozzle N, the size and shape of the substrate G, etc. At this time, the printing path calculation step S2 can be performed in real time using the processing power of the controller 50, and the calculated result can be applied to the printing step S3 immediately.

[0115] In particular, the nozzle N grade information acquired in test step S1 plays a crucial role in this calculation process. In test step S1, nozzle N is classified and managed into grades A, B, C, and D based on criteria such as whether ink adheres, the adherence location, and the volume of adhered ink I. This nozzle N grade information can be applied when calculating the printing path.

[0116] When calculating the printing path, the program is set to prioritize the use of higher-grade nozzles (N). For example, in sections with high print quality requirements, the optimized path can use only A-grade nozzles (N), while in sections with slightly lower quality requirements, the path can be adjusted to use either B-grade or C-grade nozzles (N). In this way, the printing path can be flexibly adjusted according to the status and grade of the nozzles (N), thereby improving overall print quality and minimizing defective prints.

[0117] Alternatively, the algorithm can also be implemented in hardware. The algorithm can be executed by dedicated hardware such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC) within the controller 50. This hardware unit offers the advantages of maximizing computational speed, rapidly processing large-scale data, and quickly performing complex calculations.

[0118] The program or algorithm considers the nozzle N rating information to optimize the number and position of printing paths, thereby maximizing print quality while minimizing ink waste. Furthermore, when determining the order in which printing paths are applied, printing efficiency can be improved by prioritizing the printing of specific areas or by forming a specific pattern before filling other areas.

[0119] The algorithm used in the printing path calculation step S2 will be explained in further detail below. In the printing path calculation step S2, the number of printing paths to be applied in the printing step S3, the positions of the printing paths, and the order in which the printing paths are applied can be calculated. The length of the printhead unit 40 in the first direction X is less than the length of the substrate G in the first direction X. Therefore, to complete the printing of one substrate G by the printhead unit 40, multiple printing operations are required. The position of the printhead unit 40 changes each time printing is performed. Depending on the position of the printhead unit 40, the printing path for printing on the substrate G changes. This printing path can also be called a printing pass (Swath). That is, multiple printing passes are required to complete the printing of one substrate G.

[0120] The position of the printing path can correspond to the printing position of the printhead unit 40. The position of the printing path can be determined according to the user-preset unit position change of the printhead unit 40. For example, when the user moves the position of the printhead unit 40 by a set unit distance, the value obtained by dividing the length of the substrate G in the first direction X by the set unit distance is the maximum number of printing paths that can be used, and the position of each printing path separated by the set unit distance is the position of the printing path that can be applied in printing step S3.

[0121] Typically, the application sequence of the printing path can be from one side of the substrate G to the other. Alternatively, the printing path can be applied sequentially along the first direction X from one edge of the substrate G to the other. However, this sequence is not limited to this. For example, considering that the printhead unit 40 has a relatively low chance of participating in printing at the two side edges of the substrate G, while the printhead unit 40 has a relatively high chance of participating in printing at the central part of the substrate G, the printing path can be applied starting from the two side edges of the substrate G, and then applied to the central part of the substrate G, thus determining the application sequence of the printing path.

[0122] The following explanation focuses on the method for calculating the number of printing paths.

[0123] In step S21, the process of determining whether a set number of printing paths can meet the user's request conditions begins. The set number can be N. N can be a natural number greater than or equal to 1. The initial number of printing paths to which the algorithm of printing path calculation step S2 is applied, i.e., the set number, can be determined based on various factors. The algorithm of printing path calculation step S2 is used to obtain the number, arrangement, and order of printing paths to be applied in printing step S3.

[0124] For example, the user can input substrate information such as the size of the substrate G, and information about the RGB color filter layer to be formed on the substrate G, through the controller 50. The controller 50 can calculate the set quantity based on this information. The mathematical formula used to calculate the set quantity can be pre-stored in the controller 50. Based on the substrate information and the color filter layer information, a set quantity lower than the predicted quantity (a quantity less than the predicted quantity) can be selected, where the predicted quantity is the quantity that is expected to meet the user's request. This is because when the selected set quantity is higher than the predicted quantity (a quantity greater than the predicted quantity), unnecessary printing paths may be applied during the printing of the substrate G.

[0125] In step S22, the amount of ink to be filled onto the substrate G is calculated based on the set number of printing paths. The ink filling amount can be calculated based on the number of printing paths and the amount of ink that the printhead unit 40 can fill in a single printing path. In different cases, the information related to the nozzle N's grade can be applied for calculation. The more high-grade nozzles N participating in each printing path, the more ink may be filled. The more low-grade nozzles N, the less ink may be filled.

[0126] In step S23, it is confirmed whether the ink filling amount calculated in step S22 can meet the target volume set by the user.

[0127] Due to the mechanical limitations of the drive components such as piezoelectric elements, the amount of ink that can be filled onto the substrate G in a single printing path is limited by the nozzles N of the printhead unit 40. Furthermore, in order to compensate for poor spraying areas caused by low-grade nozzles N, the user may limit the amount of ink I that the printhead unit 40 can spray per unit stroke. Therefore, when the number of printing paths is small, the printing paths are sparsely arranged throughout the entire area of ​​the substrate G. In this case, the ink I filling volume on the substrate G may be small. Conversely, when the number of printing paths is large, the printing paths are densely arranged throughout the entire area of ​​the substrate G. In this case, the ink I filling volume on the substrate G may be larger.

[0128] If the first target volume for forming the color filter layer requested by the user cannot be met, the number of printing paths is increased in step S24. For example, if the first target volume for forming the color filter layer requested by the user cannot be met by N printing paths, the number of printing paths is increased by 1 each time, and it is confirmed whether the ink I filling amount requested by the user can be met.

[0129] If the first target volume of ink I requested by the user is met, step S25 determines whether the target number of spacer pixels can be filled. For example, the user determines whether X% of the spacer pixels in the entire spacer pixel matrix can be filled to form columnar spacers CS. This is because it is not necessary to form columnar spacers CS in all spacer pixels. For example, if columnar spacers CS are formed only in X% of the spacer pixels in the entire spacer pixel matrix, the spacing between the TFT substrate and the color filter can be properly maintained in the bonding process with the TFT substrate. The X% can be a value obtained in advance by the user through testing, etc.

[0130] In step S25, it is determined whether increasing the ink ejection amount I by the printhead unit 40 can fill a total of X% of the spacer pixels along the printing path determined in steps S22 and S23. Filling the spacer pixels refers to satisfying the second target volume required to form the columnar spacers CS.

[0131] For example, when a user sets X% to 50%, and such Figure 10 As shown, when there are 24 spacer pixels used to form columnar spacers CS, the controller 50 determines whether it is possible to fill the second target volume in more than 50% of the spacer pixels by implementing the algorithm of printing path calculation step S2.

[0132] For example, when the second target volume can be filled in the spacer pixels used to form 14 columnar spacers CS, it can be considered that the condition is met since it means that about 58% of the spacer pixels are filled.

[0133] In addition, Figure 10 In the diagram, diagonal lines represent the spacer pixels that fill the target volume. For example... Figure 10 As shown, for spacer pixels that are determined to be unable to fill the target volume, ink is not ejected at all (I), thereby minimizing the consumption of ink (I).

[0134] Furthermore, the spacer pixels to be ejected with ink I can be randomly selected. However, even if randomly selected, the selected spacer pixels should be evenly distributed throughout the entire area of ​​the substrate G so that the bonding process described later can be performed correctly. Therefore, the controller 50 can evenly set the selection probability distribution of the spacers throughout the entire area of ​​the substrate G. In this case, the selection probability can be the same as X% set in step S24.

[0135] Furthermore, the ink I used to fill the spacer pixels is ink I that does not include the aforementioned light-emitting elements. For example, the blue ink I(B) of the aforementioned red ink I(R), green ink I(G), and blue ink I(B) can be used to fill the spacer pixels. If the columnar spacers CS formed at the spacer pixels contain light-emitting elements, the manufactured display panel will unnecessarily consume power and will reduce the accuracy of the image output by the light-emitting elements.

[0136] Furthermore, the present invention first confirms whether a predetermined number of printing paths can fill the first target volume required to form the RGB color filter layer, and then confirms whether a predetermined percentage of the spacer pixels can be filled. That is, the present invention confirms the maximum number of spacer pixels that can be filled when controlling the ejection amount of the printhead unit 40 based on printing paths that fill all RGB color filter layers. And when the confirmed number exceeds the predetermined target number (a predetermined percentage), the printing apparatus 1 can perform printing based on an image rendered based on the printing paths.

[0137] Figure 11 It is an illustration of using through Figure 9 The algorithm calculates the cross-sectional view of the RGB color filter layer and columnar spacers formed by the printing path.

[0138] Reference Figure 11 Based on the printing path calculated in step S2 of one embodiment of the present invention, a printing process can be manufactured as follows: Figure 11 The color filter shown. (Refer to...) Figure 11The color filter may include: a substrate G; a black matrix BM; an RGB color filter layer formed of RGB ink I; an overcoat layer COT1 coated on the RGB color filter layer for leveling uneven heights; and a transparent electrode (indium tin oxide (ITO)) COT2 formed on top in the form of a thin film to drive liquid crystal after subsequent bonding with a TFT substrate.

[0139] Through the above printing step S3, the RGB color filter layer and the columnar spacer CS can be formed in one step. In addition, the height of the columnar spacer CS formed by printing step S3 can be greater than the sum of the heights of the RGB color filter layer, the capping layer COT1, and the transparent electrode COT2.

[0140] Figure 12 This is a flowchart illustrating a substrate processing method according to an embodiment of the present invention.

[0141] Reference Figure 12 An embodiment of the substrate processing method of the present invention may include a testing step S1, a printing path calculation step S2, a printing step S3, a first coating step S4, a second coating step S5, and a bonding step S6.

[0142] The testing step S1, printing path calculation step S2, and printing step S3 are the same as described above. The first coating step S4 can be the step of forming the cover layer COT1. The second coating step S5 can be the step of coating the transparent electrode COT2. The bonding step S6 can be the step of bonding the color filter obtained through the testing step S1, printing path calculation step S2, printing step S3, first coating step S4, and second coating step S5 to the TFT substrate.

[0143] The above detailed description is for illustrative purposes. Furthermore, the foregoing content is intended to describe preferred embodiments of the invention, which can be implemented in various combinations, variations, and usage environments. That is, variations or modifications can be made within the scope of the inventive concept disclosed in this specification, within the equivalent scope of the disclosed content, and / or within the scope of the relevant technical or knowledge field. The described embodiments are intended to illustrate the optimal implementation of the technical concept of the invention, and various variations can be made according to the specific application field and use of the invention. Therefore, the detailed description of the invention is not intended to limit the scope of protection to the disclosed embodiments. The claims should be interpreted to cover other embodiments.

Claims

1. A printing method, the method comprising: A printing path calculation step for calculating at least one printing path applied during the printing of the substrate; as well as The printing steps of printing on the substrate are performed using the printing path calculated in the printing path calculation step. In the printing step A color filter layer and columnar spacers with a height higher than the color filter layer are simultaneously formed on the substrate.

2. The printing method according to claim 1, wherein, The printing path calculation steps include: Step a, determine whether the first target volume for forming the color filter layer is satisfied when a set number of printing paths are applied to the printing step; Step b: When the set number of printing paths meets the first target volume, determine whether it is possible to fill the target number or more with the second target volume among the multiple spacer pixels that will form the columnar spacers. Step b is performed after step a.

3. The printing method according to claim 2, wherein, In step b, it is determined whether the amount of ink ejected by the printhead unit in step a, which maintains the set number of printing paths but increases the amount of ink ejected to form the color filter layer, is sufficient to fill the target number or more.

4. The printing method according to claim 2, wherein, If the first target volume cannot be filled in step a, or if the target number in the plurality of spacer pixels cannot be filled with the second target volume in step b, the set number is increased, and step a is executed.

5. The printing method according to claim 2, wherein, The spacer pixels selected in step b are randomly selected, and a selection probability distribution for selecting the spacer pixels is uniformly set throughout the entire area of ​​the substrate.

6. The printing method according to claim 1, wherein, The ink sprayed onto the substrate in the printing step includes various types, at least one of which includes a light-emitting element, and at least one of which does not include the light-emitting element.

7. The printing method according to claim 6, wherein, The ink used to form the columnar spacers is of a type that does not include the light-emitting element.

8. The printing method according to claim 7, wherein, The ink used to form the color filter layer includes red ink, green ink, and blue ink. The ink used to form the columnar spacers is composed of the blue ink. The red ink and the green ink include the light-emitting element. The blue ink does not include the light-emitting element.

9. A manufacturing method, the method comprising: A printing step involving spraying ink onto a substrate forming a black matrix to simultaneously print a color filter layer and columnar spacers higher than the color filter layer.

10. The manufacturing method according to claim 9, wherein the method comprises: After forming the color filter layer and the columnar spacers, a first coating step is performed to form a cover layer on the substrate. as well as Following the first coating step, a second coating step is performed to form a transparent electrode in the form of a thin film on the upper part of the cover layer.

11. The manufacturing method according to claim 10, wherein, The upper end of the columnar spacer formed in the printing step is located above the upper surface of the transparent electrode.

12. The manufacturing method according to claim 9, further comprising: A printing path calculation step is performed to calculate at least one printing path applied during the printing of the substrate. In the printing step, the printhead unit that ejects the ink applies the printing path calculated in the printing path calculation step to print the color filter layer and the columnar spacers.

13. The manufacturing method according to claim 12, wherein, The printing path calculation steps include: Step a, determining whether applying a set number of printing paths to the printing step satisfies the first target volume for forming the color filter layer; and Step b: When the set number of printing paths meets the first target volume, determine whether it is possible to fill the target number or more with the second target volume among the multiple spacer pixels that will form the columnar spacers. Step b is performed after step a.

14. The manufacturing method according to claim 13, wherein, In step b, it is determined whether the jetting amount of the printhead unit in step a, which maintains the set number of printing paths but increases the amount of ink ejected to form the color filter layer, is sufficient to fill the target number or more.

15. The manufacturing method according to claim 13, wherein, If the first target volume cannot be filled in step a, or if the target number in the plurality of spacer pixels cannot be filled with the second target volume in step b, the set number is increased, and step a is executed.

16. The manufacturing method according to claim 13, wherein, The spacer pixels selected in step b are randomly selected, and a selection probability distribution for selecting the spacer pixels is uniformly set throughout the entire area of ​​the substrate.

17. The manufacturing method according to claim 9, wherein, The ink used to form the color filter layer includes red ink, green ink, and blue ink. The ink used to form the columnar spacers is composed of the blue ink. The red ink and the green ink include the light-emitting element. The blue ink does not include the light-emitting element.

18. A printing apparatus comprising: Printing table; The conveying unit conveys the substrate on the printing table; The printhead unit sprays ink onto the substrate; as well as The controller controls at least one of the conveyor unit, the printhead unit, and the printing table. The controller is configured to, Calculate the printing path to be used when printing the substrate, and perform printing on the substrate according to the calculated printing path. During the printing process, the printhead unit and the delivery unit are controlled to spray ink onto the sub-pixels and spacer pixels. The sub-pixels are used to form a color filter layer on the substrate, and the spacer pixels are used to form columnar spacers.

19. The printing apparatus according to claim 18, wherein, The controller is configured to, Calculate the number of printing paths that satisfy the requirement to spray onto the first target volume of the sub-pixel. Based on the calculated printing path, the number of spacer pixels that the printhead unit can fill is calculated, and it is determined whether the calculated number of spacer pixels is greater than or equal to the target number. When the calculated number of spacer pixels is greater than or equal to the target number, the nozzle unit and the conveying unit are controlled to perform the printing using the calculated printing path.

20. The printing apparatus according to claim 19, wherein, The printhead unit is configured to eject at least one of the ink including a light-emitting element and the ink excluding the light-emitting element. The controller is configured to, The nozzle unit is controlled to spray ink, excluding the light-emitting element, onto the spacer pixels.

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