Coating method using an inkjet device

Abstract

The present invention relates to a coating method for coating a plurality of elements (81) arranged in a predetermined element pitch (CP) in an arrangement direction on a coating target with a predetermined number of droplets. The present coating method includes: an observation step of observing a droplet position deviation of a droplet ejected from each nozzle (N) with respect to a target droplet position set in advance for each nozzle (N); a generation step of selecting a drive nozzle from the plurality of nozzles (N) based on data of a design position of each nozzle (N) and data on the droplet position deviation of each nozzle, and generating replacement arrangement data; and a coating step of controlling a head unit (2) using the replacement arrangement data to eject the predetermined number of droplets to the plurality of elements (81), respectively.

Description

Technical Field

[0001] This invention relates to a coating method using an inkjet device. Background Technology

[0002] In recent years, the method of using inkjet devices to manufacture devices has attracted attention.

[0003] Patent Document 1 discloses a method for manufacturing a color filter having multiple filter elements formed on a substrate by simultaneously ejecting ink while scanning the inkjet head relative to the substrate. In this method, multiple coloring heads that eject inks of R, G, and B are moved in a relative movement direction, and ink is ejected from the ejection outlet of each coloring head at predetermined times.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-108820 Summary of the Invention

[0007] One aspect of the present invention relates to a coating method, which uses a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing to coat a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object with a predetermined number of droplets. The coating method includes: an observation step, observing the droplet position offset from each of the nozzles relative to a target droplet position preset for each of the nozzles in the arrangement direction; a generation step, selecting a drive nozzle from the plurality of nozzles as a drive object based on data of the design position of each nozzle and data regarding the droplet position offset of each nozzle, and generating permutation arrangement data as arrangement data of the drive nozzle; and a coating step, using the permutation arrangement data to control the head unit to spray the predetermined number of droplets onto the plurality of elements respectively. Attached Figure Description

[0008] Figure 1 This is a schematic diagram showing an example of the structure of an inkjet device.

[0009] Figure 2 This is a diagram showing an example of the nozzle position in the design state of the head unit.

[0010] Figure 3 This is a diagram showing an example of the nozzle position of the manufactured head unit.

[0011] Figure 4 It is a diagram used to illustrate the positional deviation caused by the characteristics of the nozzle's ejection angle.

[0012] Figure 5This is a flowchart illustrating the processing flow of the coating method according to this embodiment.

[0013] Figure 6 This is a flowchart illustrating the processing flow of the first position correction process.

[0014] Figure 7 This is a diagram illustrating the data processing flow of the coating method of this embodiment.

[0015] Figure 8 This is a diagram illustrating an example of how the data is processed in each table.

[0016] Figure 9 This is a diagram showing an example of the nozzle position of the head unit in a comparative example.

[0017] Figure 10 This is a diagram showing the nozzles allocated to the elements during printing on the workpiece according to the design values.

[0018] Figure 11 It is shown in Figure 10 The diagram shows an example of a situation where there is a positional offset and an unusable nozzle.

[0019] Figure 12 For the variant example, it is equivalent to Figure 2 The image.

[0020] Figure 13 For the variant example, it is equivalent to Figure 3 The image.

[0021] Figure 14 This is another example of the nozzle position in the design state of the head unit.

[0022] Figure 15 This is another example of the nozzle position in the design state of the head unit.

[0023] Figure 16 This is a flowchart illustrating the processing flow of a modified coating method.

[0024] Explanation of reference numerals in the attached figures

[0025] 2: Head unit

[0026] 7: Workbench

[0027] 8: Panel (Object to be coated)

[0028] 81: Components

[0029] N: Nozzle. Detailed Implementation

[0030] Typically, multiple inkjet heads are combined to form an inkjet head unit by lengthening the inkjet head in a direction orthogonal to the scanning direction of printing. However, if the inkjet head unit becomes longer, it is prone to stretching and deformation, which can sometimes result in a physical positional shift from the ideal nozzle position.

[0031] Ideally, the inkjet head nozzles should eject droplets directly downwards. However, sometimes the characteristics of the nozzles can cause a deviation in the flight angle of the droplets ejected from the nozzles.

[0032] The offset of the nozzle position and the offset of the droplet's flight angle result in an offset of the droplet's landing position (the actual landing position deviates from the target landing position). Therefore, in the prior art, when applying ink to the elements (cells) of a display panel, it is difficult to ensure that a specified number of droplets fall onto each element. In recent years, with the continuous development of higher image quality in displays and narrower spacing between elements, this problem has become even more pronounced.

[0033] One objective of this invention is to provide a coating method that enables a specified number of droplets to fall onto a coating target.

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiments described below are all preferred examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions of constituent elements, and connection methods shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, in the constituent elements of the following embodiments, constituent elements not described in the independent technical solution representing the highest-level concept of the present invention will be described as arbitrary constituent elements.

[0035] <Inkjet device>

[0036] First, use Figure 1 as well as Figure 2 The structure of the inkjet device of this embodiment will be described.

[0037] The inkjet unit 1 includes: a head unit 2, which has multiple inkjet heads 3 (see reference). Figure 2 ); and workbench 7, which is used to hold panel 8.

[0038] The inkjet unit 1 is configured to allow the panel 8 on the worktable 7 to move relative to the head unit 2 in the scanning direction. During this relative movement, the inkjet unit 1 applies ink from the nozzles N formed on the inkjet head 3 to the element 81 on the panel 8. For example, the inkjet unit 1 is used to apply droplets of ink containing organic functional materials onto the element to form an organic functional layer.

[0039] In this embodiment, a plurality of elements 81 are arranged along an arrangement direction to form a first element column 82, another plurality of elements 81 are arranged along the arrangement direction to form a second element column 83, and yet another plurality of elements 81 are arranged along the arrangement direction to form a third element column 84. The second element column 83 is adjacent to the first element column 82 in the scanning direction. The third element column 84 is adjacent to the second element column 83 in the scanning direction. In this example, the second element column 83 and the third element column 84 are not offset relative to the first element column 82 in the arrangement direction. However, the second element column 83 and the third element column 84 may also be offset relative to the first element column 82 in the arrangement direction.

[0040] In this embodiment, each element 81 has an elongated oval shape. However, each element 81 may also have a circular, quadrilateral, hexagonal, or other shapes.

[0041] The inkjet device 1 can coat ink in an RGB stripe arrangement on the first element column 82, the second element column 83 and the third element column 84, or it can coat ink in a Pentile arrangement on the first element column 82, the second element column 83 and the third element column 84.

[0042] It should be noted that in this embodiment, three types of elements are included for RGB (three elements that emit different inks), with the first element column 82, the second element column 83, and the third element column 84 corresponding to RGB respectively. However, this is not a limitation; the panel 8 may include only one type of element or multiple types of elements. Furthermore, hereinafter, the elements corresponding to RGB will be referred to as red elements, green elements, and blue elements respectively.

[0043] On panel 8, at specified intervals in the arrangement direction (refer to...) Figure 2 The CP is formed with elements (coloring areas). In this invention, the spacing between the elements in the arrangement direction is called the "element spacing CP".

[0044] -Workbench-

[0045] The worktable 7 is configured to hold a panel 8, which is the object to be coated with ink. The worktable 7 has a moving mechanism (not shown) that moves the held panel 8 in the scanning direction and in an alignment direction orthogonal to the scanning direction. The moving mechanism of the worktable 7 operates, for example, based on a control signal output from the drive control unit described later. The moving mechanism of the worktable 7 can employ a structure commonly known in the past.

[0046] -Inkjet Unit-

[0047] exist Figure 2 The upper part shows an example of the ideal structure, i.e., the structure of the head unit 2 in the design phase. The head unit 2 has multiple inkjet heads 3 arranged in parallel with each other.

[0048] The inkjet head 3 is elongated and arranged at a predetermined angle relative to the scanning direction. In each inkjet head 3, multiple nozzles N are formed at equal intervals along its long side. Furthermore, the multiple inkjet heads 3 are arranged such that the spacing between the nozzles N is equal relative to the arrangement direction. The nozzle spacing NP in the arrangement direction is, for example, approximately 20 μm. By arranging the inkjet heads 3 at an angle, a narrow-pitch head unit 2 can be achieved.

[0049] In this invention, such as Figure 2 As shown, the position of nozzle N, ideally configured with equal spacing between nozzles NP, is called the "design position of nozzle N". Ideally, the droplets ejected from nozzle N fall directly downwards. That is, ideally, the design position of nozzle N is equal to the droplet falling position in both the alignment direction and the scanning direction.

[0050] It should be noted that, for ease of explanation in the following description, when explaining each nozzle N separately, the reference numerals N1, N2, N3, ... may be used sequentially from the left side of the attached drawing. In this case, the same reference numerals as those used for the nozzles may be used to indicate the position of each nozzle. Furthermore, the numerical portion after removing N from N1, N2, N3, ... is called the logical nozzle number of each nozzle N. Figure 2 The same applies to other figures.

[0051] Figure 3 The upper part shows an example of the structure (actual state) of the head unit 2 after manufacturing.

[0052] As mentioned earlier, nozzles N are ideally arranged with equal spacing in the arrangement direction. However, in reality, as... Figure 3 As shown above, there is a situation where the "designed position of nozzle N" and the actual nozzle position are offset due to the expansion, contraction, and deformation of the head unit 2. This offset is caused by, for example, the following reasons: (1) the expansion and contraction of each inkjet head 3, (2) the installation error when installing the plate (head unit 2) that fixes multiple inkjet heads 3, and (3) the expansion and contraction of the fixed position of the inkjet head 3 accompanied by the expansion and contraction of the material caused by the heat of the plate that fixes multiple inkjet heads 3. Therefore, the accuracy of the actual assembled nozzle position includes the absolute accuracy error of the plate and head that install the inkjet head, as well as the assembly accuracy error during assembly.

[0053] Furthermore, there is a possibility that the flight angle of the droplets ejected from nozzle N may deviate, causing the droplet position to shift relative to directly below the nozzle. In fact, when the inkjet head 3 ejects ink from nozzle N, it has the ejection angle characteristics of each nozzle. Therefore, the ejection position is determined based on the gap G between the inkjet head 3 and the panel 8 to be coated.

[0054] Figure 4 (a) is a diagram showing the droplet position on panel 8 as viewed from above, where the nozzle position of inkjet head 3 has shifted due to the characteristics of the ejection angle. Figure 4 (b) is viewed from a horizontal perspective and Figure 4 (a) A diagram showing the same droplet location. It should be noted that in... Figure 4 In (a), N1 to N5 represent the designed positions of each nozzle. That is, in Figure 4 In this configuration, nozzles N1 to N5 are positioned at their designed locations. For example... Figure 4 As shown in (a) and (b), due to the characteristics of the ejection angle, the droplet landing positions P1 to P5 of the corresponding droplets are offset relative to the designed positions N1 to N5 of each nozzle. The technical feature of this invention is that even when the droplet landing position offset occurs due to such physical position offset of the nozzle N and ejection angle offset of the nozzle N, a predetermined number of droplets can still be dropped onto the coating target. Details will be explained later in the "Coating Method Using an Inkjet Apparatus".

[0055] -Computation Processing Department-

[0056] The arithmetic processing unit 4 performs processing for controlling the inkjet device 1. The arithmetic processing unit 4 includes a drop position calculation unit 41 and a correction processing unit 42 that performs the first position correction processing and the second position correction processing described later. The arithmetic processing unit 4 is implemented, for example, by a microcomputer or CPU (processor) with one or more chip structures.

[0057] (Drip position calculation unit)

[0058] The drop position calculation unit 41 calculates the position offset of each drop position P from the target drop position based on the imaging results obtained by photographing the drop position P of the droplets ejected from each nozzle N. The target drop position is the drop position of each droplet when the droplets are ejected directly downward from the designed position of each nozzle N.

[0059] -Storage Department-

[0060] The storage unit 5 has the function of storing information such as programs used to operate the CPU (microcomputer) and processing results in the CPU (microcomputer). In addition, the storage unit 5 has a first region 51, a second region 52, and a third region 53.

[0061] like Figure 7 As shown, the first region 51 stores the drop position offset data T2, which will be described later. The second region 52 stores the nozzle arrangement data T1 and the nozzle correction table T3, which will be described later. The third region 53 stores the printing data T4 and the target coordinate data T5.

[0062] Nozzle arrangement data T1 is data that establishes a connection between logical nozzle information and physical nozzle information and is saved.

[0063] Logical nozzle information is data about the designed location of the nozzles; it establishes a link between logical nozzle numbers and the location information of the nozzles corresponding to each logical nozzle number. Figure 8 The top left shows an example of nozzle arrangement data T1. Figure 8 In the example, the position of nozzle N1, which has the logical nozzle number "1", is set as the origin (zero point). Figure 8 An example is shown where nozzles N are arranged with a 100 μm spacing in the arrangement direction.

[0064] The physical nozzle information includes the head number indicating the position of the inkjet head 3 in head unit 2 and the physical nozzle number indicating the position of the nozzle N in each inkjet head 3. For example, in Figure 8 In the middle, as Figure 2 The inkjet heads are numbered sequentially from inkjet head 3 on the left side of the attached diagram as 1, 2, 3, ... Additionally, within each inkjet head 3, the nozzles are numbered sequentially from nozzle N on the left side of the attached diagram as 1, 2, 3, 4. For example, for... Figure 2 The leftmost nozzle label of inkjet head 3 on the left Figure 8 The physical nozzle number 1 of the head number 1 is associated with the logical nozzle number 1 (nozzle N1).

[0065] Set the nozzle arrangement based on physical nozzle information to physical nozzle arrangement 35, and set the nozzle arrangement based on logical nozzle information to logical nozzle arrangement 36.

[0066] Print data T4 shows the driving methods of multiple nozzles at various points during scanning of head unit 2. For example, the multiple points include a first point where the nozzle is on a red element, a second point where the nozzle is on a green element, and a third point where the nozzle is on a blue element. The driving methods include a first drive to eject ink and a second drive to prevent ink ejection. For example, the multiple nozzles include a red nozzle capable of ejecting red ink that passes sequentially over red, green, and blue elements during scanning of head unit 2. Regarding such a red nozzle, print data T4 shows the first drive at the first point, the second drive at the second point, and the third drive at the third point.

[0067] Additionally, multiple nozzles include nozzles that pass between elements in the alignment direction but not over any element during scanning of head unit 2. Regarding such nozzles, printing data T4 shows a second drive at any of the first, second, and third timings.

[0068] It should be noted that the second drive to prevent ink from being ejected refers to applying voltage to the piezoelectric element to the extent that ink is not ejected from the nozzle.

[0069] The target coordinate data T5 defines the starting coordinates, component size, and spacing between components for the component configuration. It should be noted that multiple sets of target coordinate data T5 can also be prepared. This allows for checking the number of nozzles allocated to all components for multiple target component positions.

[0070] It should be noted that the storage unit 5 (memory) can be housed within the same chip as the arithmetic processing unit 4, or it can be housed in a separate chip. Alternatively, the storage unit 5 can be implemented using storage media such as HDD (Hard Disk Drive) or SSD (Solid State Drive).

[0071] -Drive Control Department-

[0072] The drive control unit 6 has the following functions: during a series of actions that involve the inkjet head 3 scanning relative to the panel 8 while ejecting ink, it moves the worktable on which the panel 8 is mounted, or controls the drive of the nozzle N. The drive control unit 6 is implemented, for example, by one or more microcomputers or CPUs (processors) with a chip structure.

[0073] Specifically, the drive control unit 6 reads the printing data T4 from the storage unit 5 and, based on the printing data T4, outputs the drive waveforms received from the drive waveform signal generator (not shown) to each nozzle N of the inkjet head 3. For example, if the printing data T4 indicates a first drive at a certain time with respect to a particular nozzle, the drive control unit 6 supplies a drive waveform for ink ejection to that nozzle at that time. If the printing data T4 indicates a second drive at another time with respect to that nozzle, the drive control unit 6 supplies a drive waveform for preventing ink ejection to that nozzle at that time.

[0074] In addition, the drive control unit 6 has the function of moving the panel 8 or the head unit 2 in the arrangement direction based on the first head movement amount and the second head movement amount described later.

[0075] It should be noted that the drive control unit 6 can also be divided into a module for driving control of the axis (worktable, etc.) system and a module for driving control of the head's ejection.

[0076] <Coating Method Using Inkjet Devices>

[0077] The following is for reference Figure 3 , Figure 5 , Figure 6 as well as Figure 7 The coating method using inkjet apparatus 1 will be specifically described. This description focuses on a coating method in which a predetermined number of droplets of ink are applied to the aforementioned element 81 disposed on panel 8 using nozzles N. The nozzles N are designed with a nozzle spacing NP, but actually have a positional offset. This coating method includes an observation step, a generation step, a printing data generation step, and a coating step. This coating method can be implemented wholly or partially by a computer equipped with a processor and a memory storing the program executed by the processor. The processor may, for example, be included in the arithmetic processing unit 4 and the drive control unit 6 as described above. The memory may, for example, be a storage unit 5.

[0078] -Observation Procedure-

[0079] During the observation process, the positional deviation of the droplets ejected from each nozzle is observed.

[0080] Specifically, in Figure 5 In step F1, print data is generated. Figure 7 F10), a pattern for detecting the location of a printed drop (hereinafter referred to as the drop pattern) Figure 7 (F11). When printing the droplet pattern, more than one droplet is ejected from each nozzle N.

[0081] In the next step F2, the drip pattern printed in step F1 is observed using a camera (illustration omitted) for drip observation. Figure 7 (F21). The drop position calculation unit 41 calculates the position offset of the drop pattern from the target drop position based on the camera's shooting results. Figure 7 (F22).

[0082] At this time, as Figure 4 As shown in (a), the positional offset between the scanning direction and the arrangement direction is observed. In this embodiment, at least the information on the drop position offset in the arrangement direction (hereinafter referred to as "drop position offset data T2") is calculated, and this drop position offset data T2 is used. That is, in the following case, when simply referred to as "drop position offset data T2", it refers to the information on the drop position offset in the arrangement direction. Figure 8 The bottom left shows an example of the drop position offset data T2.

[0083] It should be noted that the drop position offset in the scanning direction can be eliminated, for example, by adjusting the timing of ink ejection from each nozzle N. The acquired drop position offset data T2 is stored in the first region 51 of the storage unit 5.

[0084] -Production Process-

[0085] In the generation process, based on the nozzle arrangement data T1 and the drop position offset data T2, a driving nozzle is selected as the driving object, and replacement arrangement data (updated arrangement data) is generated as the arrangement data of the driving nozzle.

[0086] The following is for reference Figure 5 , Figure 6 The specific processing flow of the production process is explained.

[0087] First of all, Figure 5 In step F3, based on the aforementioned nozzle arrangement data T1 and the drip position offset data T2 calculated in step F2, a position correction process (hereinafter referred to as the first position correction process) is performed to optimize the nozzle arrangement data.

[0088] (First position correction processing)

[0089] Figure 6 This is a flowchart showing the details of the first position correction process (equivalent to the first search step).

[0090] First, in step F31, based on the nozzle arrangement data T1 and the drop position offset data T2, a rearrangement process is performed on the nozzles N according to the accuracy guarantee distance in the arrangement direction of each nozzle N. In this rearrangement, the accuracy guarantee distance needs to be set according to the necessary accuracy for the printing object. Figure 8 The nozzle correction table T3 shows the results of the above rearrangement with the accuracy guarantee distance set to 0.045 mm.

[0091] As a specific process, for each nozzle N's design position, nozzles N whose droplet position is within the accuracy-guaranteed distance range are selected and their associations are re-established, thereby generating a nozzle correction table T3. More specifically, nozzles that eject droplets relative to the target droplet position corresponding to the nozzle N's design position are searched for within the accuracy-guaranteed distance range. If such a nozzle can be found, it is selected as the drive nozzle corresponding to the nozzle N's design position. If no nozzle can be found, no nozzle is selected as the drive nozzle corresponding to the nozzle N's design position. For a nozzle N's design position, if there are more than two physical nozzles within its accuracy-guaranteed distance range, the physical nozzle closest to the nozzle N's design position is selected and its association is established. Furthermore, unselected physical nozzles are set as "non-dispensing nozzles" that do not eject droplets.

[0092] For example, in Figure 8In the example of the drip position offset data T2, the drip position offsets of nozzles N4 and N7 relative to their designed nozzle positions exceed the accuracy guarantee distance of 0.045 mm. Therefore, nozzles N4 and N7 cannot be assigned as drive nozzles at their respective designed positions. Next, regarding the designed position of nozzle N5, when comparing the drip position P4 of nozzle N4 and the drip position P5 of nozzle N5, the drip position P4 of nozzle N4 is closer to the designed position of nozzle N5. Therefore, in the nozzle correction table T3, nozzle N with logical nozzle number "4" is set as the drive nozzle at the designed position of nozzle N5. Furthermore, nozzles N with logical nozzle numbers "5" and "7", which are not assigned as drive nozzles, are set as non-discharge nozzles.

[0093] In the next step F32, updated nozzle information Z6 is generated. Updated nozzle information Z6 includes updated arrangement data T6 based on nozzle arrangement data T1 and updated position offset data T7 based on drop position offset data T2.

[0094] Specifically, the updated arrangement data T6 is obtained by updating the logical nozzle and physical nozzle association of the nozzle arrangement data T1 in a manner corresponding to the updated new nozzle positions shown in the nozzle correction table T3 above. The updated position offset data T7 is obtained by updating the drip position offset data T2 in a manner corresponding to the updated new nozzle positions shown in the nozzle correction table T3.

[0095] In the next step F33, the first head movement amount is calculated. The first head movement amount is the offset movement amount in the arrangement direction of the head unit 2 as a whole. This offset movement amount is set in a way that minimizes the number of nozzles that are not associated during the nozzle N rearrangement process in the aforementioned step F31, i.e., the number of nozzles that do not eject. Specifically, a process is performed to search for the optimal offset movement amount within any specified range and specified spacing.

[0096] For example, if we take Figure 8Taking an example, the first head movement amount is preferably set to -0.02mm. This updates the drip position offset of nozzle N1 from +0.03mm to +0.01mm. Similarly, the drip position offsets of nozzles N2 to N7 are updated to -0.04mm, -0.01mm, +0.045mm, +0.02mm, and +0.07mm, respectively. Consequently, the drip position offset of nozzle N4 changes from +0.065mm to +0.045mm. This satisfies the aforementioned accuracy guarantee distance, allowing nozzle N4 to be assigned to the design position of logical nozzle number "4". Furthermore, nozzle N5 can be assigned to the design position of logical nozzle number "5". On the other hand, for logical nozzle number "7", no nozzle is assigned as a driving nozzle. Thus, in... Figure 8 In the example, by setting -0.02mm as the first head movement amount, one more drive nozzle can be added compared to the initial setting of the first head movement amount. In this way, the minimum first head movement amount that does not eject nozzles can be calculated.

[0097] When the processing up to this point is complete, return. Figure 5 The process then proceeds to the next step, F4.

[0098] In step F4, the nozzle correction table T3 is updated to take into account the data obtained in step F33, which is the first head movement amount. Furthermore, corresponding to the update of the nozzle correction table T3, the updated arrangement data T6 and the updated position offset data T7 are updated again.

[0099] In the next step, F5, the effectiveness / ineffectiveness of the optimization process is determined. The determination of whether optimization is needed (or whether it is effective) can also be based, for example, on whether a specified number of droplets can be ejected from each component.

[0100] If the nozzle optimization process in step F5 is ineffective, the aforementioned first head movement amount is set as the head movement amount for the inkjet unit 1 (step F6). Then, when the process in step F6 ends, the process proceeds to the next step F9 (print data generation process). The print data generation process will be explained later.

[0101] On the other hand, if the nozzle optimization process in step F5 is effective, from the viewpoint of ensuring more droplets for each element 81, a position correction process (hereinafter referred to as the second position correction process) is performed to optimize the head unit 2 as a whole plus the offset movement in the arrangement direction. In the second position correction process, a process is performed to search for the optimal offset movement that can ensure more droplets for each element 81 within any specified range and specified spacing.

[0102] (Second position correction processing)

[0103] use Figure 10 as well as Figure 11 A specific example of the second position correction process (equivalent to the second search process) will be explained.

[0104] Figure 10 This diagram illustrates the nozzles N allocated to the components when printing on panel 8 according to design values, showing the positions of the nozzles in an ideal configuration. Figure 10 As shown by the shaded line, under ideal conditions, a maximum of 3 drops of liquid can be dropped onto each component 81.

[0105] In contrast, Figure 11 The diagram illustrates examples of situations where nozzle N is misaligned and no ink is ejected. A non-ejecting nozzle refers to a nozzle that is not used on a particular print data due to nozzle misalignment or other reasons (a nozzle that does not eject any of the R, G, or B inks even once). Figure 11 In the diagram, non-ejecting nozzles are indicated by dashed lines. Nozzles N5, N13, N20, N25, N31, and N38 are designated as non-ejecting nozzles. It should be noted that... Figure 11 In this case, there is no droplet position offset caused by the characteristics of the nozzle N's ejection angle.

[0106] exist Figure 11 The upper part shows an example without the second position correction process. In this example, in the sixth element 81 from the left in the figure, due to the absence of an ejector nozzle and positional offset, the number of droplets falling into element 81 is 2. Here, from the viewpoint of achieving uniform film thickness of R, G, B within the element, the droplets are preferably uniformly coated. Therefore, the number of droplets is set corresponding to the element with the fewest droplets among all elements. In this way, in Figure 11 In this case, the number of droplets that can be sprayed onto all components in one action is only 2, which cannot ensure a sufficient number of droplets.

[0107] Therefore, as a second position correction process, a process is performed to search for the optimal offset movement amount that ensures a greater number of droplets for each element 81 within a specified search range and a specified search interval. Here, the calculated offset amount is referred to as the "second head movement amount". In this embodiment, ensuring the number of droplets to each element 81 based on the second head movement amount is prioritized over minimizing the non-ejecting nozzle based on the first head movement amount.

[0108] Specifically, for example, the "search range" can be set to -15μm to 15μm, and the "search interval" can be set to 5μm.

[0109] In this way, in addition to the first head movement calculated in step F33, the head unit 2 is moved as a whole by -15μm, -10μm, -5μm, 0μm, 5μm, 10μm, and 15μm, and the distribution state of the number of droplets relative to each element 81 at each position is calculated. For example, when the second head movement is set to -10μm, it becomes... Figure 11 The state shown at the bottom. In this way, by applying the calculated second head movement amount (-10μm), the maximum number of droplets that can be uniformly sprayed into each element in one coating operation is 3. Furthermore, if there is no bias movement amount in all other elements 81 that can achieve a droplet count of more than 3, -10μm is set as the second head movement amount.

[0110] It should be noted that this example illustrates a second position correction process performed to maximize the number of droplets ejected into each element, but it is not limited to this. For example, as a second position correction process, the offset movement can also be determined by making the droplets from each nozzle closer to the center of the element. In this case, the same action as described above can be performed. If it is desired to further improve the accuracy of the position alignment, the search spacing can be reduced. This allows for more reliable prevention of defects caused by droplets flying out of element 81.

[0111] It should be noted that, in the above explanation, it is also possible to reduce the maximum number of drops that can be dispensed from 3 to 2, without considering the nozzle rate. Additionally, if the number of droplets allocated to the element is still less than the specified number even after searching the entire search range, it can be determined that printing is impossible, and an error notification can be sent to the external device (illustration omitted).

[0112] Once the calculation of the second head movement is complete, in the next step F8, the inkjet unit 1 is set to "first head movement + second head movement" as the head movement amount. Then, when the processing of step F8 is completed, the process proceeds to the next step F9 (print data generation process).

[0113] -Printing Data Generation Process-

[0114] In the printing data generation step F9, printing data is generated using replacement arrangement data, which serves as the arrangement data for driving nozzles. Regarding the specific method for generating printing data, conventionally known methods can be applied, therefore a detailed description is omitted here. When the printing data generation step ends, the process proceeds to the next step F10 (coating step). The printing data is generated with the head unit 2 moved by a calculated head movement amount in the arrangement direction. For example, if the head movement amount is only the first head movement amount, the printing data is generated with the head unit 2 moved by the first head movement amount in the arrangement direction. If the head movement amount is the sum of the first head movement amount and the second head movement amount, the printing data is generated with the head unit 2 moved by the sum of the first head movement amount and the second head movement amount in the arrangement direction.

[0115] -Coating process-

[0116] In the coating process of step F10, the printing data generated in the printing data generation process is used to control the head unit 2 to spray a predetermined number of droplets onto each element 81. Specifically, for example, the drive control unit 6 reads the printing data based on the displacement arrangement data from the storage unit 5, and based on the printing data, outputs the drive waveform received from the drive waveform signal generator (not shown) to each nozzle N of the inkjet head 3.

[0117] As described above, by using the coating method of this embodiment, an optimal nozzle distribution state can be achieved for the component 81 to be coated. Specifically, as Figure 9 As shown, without correcting the nozzle distribution (comparative example), the element in the center of the attached figure can only ensure one droplet. In contrast, by using the coating method of this embodiment, as... Figure 3 As shown, two drops of liquid can be applied near the center of the component.

[0118] Furthermore, according to this embodiment, by moving the head unit using a first head movement amount, an optimal nozzle distribution state can be achieved for the element to be printed. Moreover, by moving the head unit using a second head movement amount in addition to the first head movement amount, the number of droplets that can be coated onto the element can be increased, or the position of the ink droplets can be aligned. It should be noted that it is also possible to move the head unit solely based on the second head movement amount, without performing movement based on the first head movement amount.

[0119] <Other Implementation Methods>

[0120] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from its spirit.

[0121] For example, in the above-described embodiments, the inkjet head 3 is configured at a predetermined angle relative to the scanning direction, but is not limited to this. For example, such as Figure 12 As shown, the inkjet heads 3 extending along the arrangement direction can also be arranged along the scanning direction. In this case, the arrangement is performed while the positions of each inkjet head 3 in the arrangement direction are staggered by the nozzle spacing NP each time. As a result, the nozzle spacing NP can be made narrower.

[0122] It should be noted that, in Figure 13 The middle shows the equivalent Figure 3 In this case, the same effect can be obtained by performing the same process as the aforementioned "coating method using an inkjet device".

[0123] In addition, such as Figure 14 As shown, it can also be based on Figure 12 The structure arranges the inkjet heads 3 at predetermined angles relative to the scanning direction. Additionally, as... Figure 15 As shown, it can also be Figure 14 The structure is treated as a unit, allowing it to be arranged at varying heights in the scanning and alignment directions. Figure 14 as well as Figure 15 In this case, the same effect can be obtained by performing the same process as the aforementioned "coating method using an inkjet device".

[0124] In the above embodiment, a rearrangement process is performed on the nozzles N with a distance guaranteed by the accuracy of the arrangement direction of each nozzle N. Figure 6 (F31). However, the present invention is not limited thereto, and the rearrangement of nozzle N may not be performed.

[0125] Such coating methods are, for example, Figure 16 As shown, the process includes a step of printing a pattern for detecting the droplet position (step F51) and a step of detecting the droplet position offset from the designed position (step F52). Steps F51 and F52 are respectively related to steps F1 and F2 (see reference). Figure 5 Since they are the same, detailed explanations are omitted.

[0126] The coating method of this modified example further includes a step (step F53) of calculating the amount of head movement of head unit 2 in the arrangement direction based on the drop position offset of each nozzle from the design position. The amount of head movement can be calculated, for example, in a way that minimizes the amount of liquid that does not spray from the nozzle, or in a way that sprays the desired number of droplets onto each element.

[0127] The coating method in this modified example further includes a step of generating printing data while the head unit 2 has moved by the calculated head movement amount (step F54). Step F54 and step F9 (see reference) Figure 5Since they are the same, detailed explanations are omitted.

[0128] The coating method of this variation also includes a step of adjusting the position of the head unit 2 in the alignment direction (step F55). Specifically, the head unit 2 moves relative to the worktable 7 by a head movement amount in the alignment direction. Step F55 can be performed before or after step F54.

[0129] The coating method of this variation also includes a coating step (step F56). Step F56 is the same as step F10, so detailed description is omitted.

[0130] As described above, the coating method of the above-described modified example uses a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, to coat a predetermined number of droplets onto a plurality of elements arranged along the arrangement direction at a predetermined element spacing on a coating object. The coating method includes the following processes: (a) observing the droplet offset in the arrangement direction relative to a target droplet position preset for each of the nozzles; (b) based on the droplet offset in the arrangement direction, searching for a bias movement amount, i.e., a second head movement amount, of the head unit in the arrangement direction such that the number of droplets coated onto each of the elements becomes a predetermined number of droplets; (c) moving the head unit in the arrangement direction by the second head movement amount; and (d) controlling the head unit to spray the predetermined number of droplets onto the plurality of elements respectively.

[0131] Alternatively, the coating method of the above-described variation uses a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, to coat a predetermined number of droplets onto a plurality of elements arranged along the arrangement direction at a predetermined element spacing on the object to be coated, wherein the coating method includes the following processes: (a) observing the droplet position offset in the arrangement direction relative to a predetermined target droplet position for each of the nozzles; (b) classifying the plurality of nozzles into used nozzles that pass over the plurality of elements and unused nozzles that do not pass over the plurality of elements; (c) based on the droplet position offset in the arrangement direction of the nozzles, searching for the head unit's offset movement amount in the arrangement direction that minimizes the number of unused nozzles, i.e., a first head movement amount; (d) moving the head unit in the arrangement direction by the first head movement amount; and (e) controlling the head unit to spray the predetermined number of droplets onto the plurality of elements respectively.

[0132] According to one aspect of the coating method of the present invention, a predetermined number of droplets can be dropped onto the coating target.

[0133] Industrial applicability

[0134] As explained above, the coating method according to the present invention is effective in applying ink to a printing object with a constant spacing with high definition, even when the nozzle position within the inkjet head cannot be changed. In particular, inkjet printing apparatuses applicable to printing of light emitters, hole transport layers, electron transport layers, color filters, or for forming uniform films in organic ELs have high industrial applicability.

Claims

1. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, and coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process, based on the design position data of each nozzle and the data regarding the drop position offset of each nozzle, selects nozzles whose drop positions are within the accuracy-guaranteed distance range from the plurality of nozzles as driving nozzles, and selects nozzles whose drop positions are outside the accuracy-guaranteed distance range as non-ejecting nozzles, generating permutation arrangement data as the arrangement data of the driving nozzles; and In the coating process, the displacement arrangement data is used to control the head unit to spray the specified number of droplets onto the plurality of elements respectively.

2. The coating method according to claim 1, wherein, The coating method further includes a printing data generation step that uses the permutation arrangement data to generate printing data. The coating process uses the printing data to control the head unit and spray the specified number of droplets onto the plurality of elements respectively.

3. The coating method according to claim 2, wherein, The coating method further includes a first search step, in which the displacement arrangement data is used to search for a first head movement amount, the first head movement amount being the offset movement amount of the head unit in the arrangement direction where the number of non-ejecting nozzles not selected as driving nozzles among the plurality of nozzles is minimized. In the printing data generation process, the printing data is generated while the head unit is moved by the first head movement amount in the arrangement direction.

4. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, and coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process, based on the design position data of each nozzle and the data regarding the drop position offset of each nozzle, selects a driving nozzle from the plurality of nozzles to be driven, and generates permutation arrangement data as the arrangement data of the driving nozzle; and In the coating process, the displacement arrangement data is used to control the head unit to spray the specified number of droplets onto each of the plurality of elements. The coating method further includes a printing data generation step that uses the permutation arrangement data to generate printing data. The coating process uses the printing data to control the head unit, thereby spraying the specified number of droplets onto each of the plurality of components. The coating method further includes a second search step, in which the displacement arrangement data is used to search for a second head movement amount, the second head movement amount being the offset movement amount of the head unit in the arrangement direction where the number of droplets coated onto each of the elements is maximized. In the printing data generation process, the printing data is generated while the head unit is moved by the second head movement amount in the arrangement direction.

5. The coating method according to claim 4, wherein, The coating method further includes a first search step, in which the displacement arrangement data is used to search for a first head movement amount, the first head movement amount being the offset movement amount of the head unit in the arrangement direction where the number of non-ejecting nozzles not selected as driving nozzles among the plurality of nozzles is minimized. In the printing data generation process, the printing data is generated when the head unit is moved in the arrangement direction by the sum of the first head movement amount and the second head movement amount.

6. The coating method according to claim 5, wherein, The second head movement is achieved by moving the worktable on which the object to be coated is placed.

7. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process, based on the design position data of each nozzle and the data regarding the drop position offset of each nozzle, selects a driving nozzle from the plurality of nozzles to be driven, and generates permutation arrangement data as the arrangement data of the driving nozzle; and In the coating process, the displacement arrangement data is used to control the head unit to spray the specified number of droplets onto each of the plurality of elements. If the result of observing the drop position offset in the observation process is that there are multiple nozzles that meet the accuracy guarantee distance relative to the design position of a nozzle, then in the generation process, the nozzle that is closest to the design position of the nozzle is selected as the driving nozzle.

8. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process, based on the design position data of each nozzle and the data regarding the drop position offset of each nozzle, selects a driving nozzle from the plurality of nozzles to be driven, and generates permutation arrangement data as the arrangement data of the driving nozzle; and In the coating process, the displacement arrangement data is used to control the head unit to spray the specified number of droplets onto each of the plurality of elements. The coating method further includes a printing data generation step that uses the permutation arrangement data to generate printing data. The coating process uses the printing data to control the head unit, thereby spraying the specified number of droplets onto each of the plurality of components. The coating method further includes a first search step, in which the displacement arrangement data is used to search for a first head movement amount, the first head movement amount being the offset movement amount of the head unit in the arrangement direction where the number of non-ejecting nozzles not selected as driving nozzles among the plurality of nozzles is minimized. In the printing data generation process, the printing data is generated while the head unit is moved by the first head movement amount in the arrangement direction.

9. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process, based on the design position data of each nozzle and the data regarding the drop position offset of each nozzle, selects a driving nozzle from the plurality of nozzles to be driven, and generates permutation arrangement data as the arrangement data of the driving nozzle; and In the coating process, the displacement arrangement data is used to control the head unit to spray the specified number of droplets onto each of the plurality of elements. The generation process includes the following steps: The nozzle is designed to eject droplets that fall within a precision-guaranteed distance relative to the target drop position corresponding to the nozzle's designed position. If the nozzle can be found, the found nozzle is selected as the drive nozzle corresponding to the designed position of the nozzle; If the nozzle cannot be found, no nozzle is selected as the drive nozzle corresponding to the designed position of the nozzle.

10. A coating method comprising using a head unit having a plurality of nozzles arranged in an arrangement direction orthogonal to the scanning direction of printing, coating a predetermined number of droplets onto a plurality of elements arranged at a predetermined element spacing along the arrangement direction on a coating object, wherein, The coating method includes: The observation process involves observing the offset of the droplets ejected from each of the nozzles relative to the target droplet position preset for each of the nozzles in the arrangement direction. The generation process involves selecting a driving nozzle from the plurality of nozzles as the driving object based on the design position data of each nozzle and the data on the drop position offset of each nozzle, and generating permutation arrangement data as the arrangement data of the driving nozzle; In the coating process, the displacement arrangement data is used to control the head unit to spray the predetermined number of droplets onto the plurality of elements respectively; and The update data generation process, following the generation process, generates updated arrangement data and updated position offset data based on the drop position offset data, in a manner corresponding to the replacement arrangement data, by updating the association between logical nozzle information representing the design position of the nozzle and physical nozzle information representing the configuration of the nozzles in the head unit.

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