Coating method using inkjet devices

Abstract

A coating method is disclosed for coating a plurality of unit cells 81 with a predetermined number of droplets, wherein the plurality of unit cells 81 are arranged on a coating object with a predetermined cell spacing CP in an arrangement direction. The coating method includes the following steps: an observation step, observing the deviation of droplets ejected from each nozzle N from a predetermined target droplet position for each nozzle N; a generation step, selecting a driving nozzle from the plurality of nozzles N based on data of the designed position of each nozzle N and data on the droplet position deviation for each nozzle, and generating displacement arrangement data; and a coating step, using the displacement arrangement data, controlling a nozzle unit 2 to eject a predetermined number of droplets from each of the plurality of unit cells 81.

Description

[Technical Field]

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

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

[0003] Patent Document 1 discloses a method in which an inkjet printhead performs a relative scan against a substrate while ejecting ink, thereby manufacturing a color filter on which a plurality of filter elements are formed. In this invention, a plurality of color heads ejecting R, G, and B inks move in a relative moving direction, and ink is ejected from the ejection outlets of each color head at predetermined time points. Prior Art Documents

[0004] Patent Document Patent Document 1: Japanese Patent Application Publication No. 2001-108820 [Summary of the Invention]

[0005] One aspect of this disclosure relates to a coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing. The nozzle unit coats each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on the object to be coated with a predetermined number of droplets. The coating method includes the following steps: an observation step, observing the deviation of droplets ejected from each of the nozzles from a drop position in the configuration direction relative to a target drop position pre-set for each of the nozzles; a generation step, 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 aforementioned drop position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., displacement configuration data; and a coating step, using the aforementioned displacement configuration data, controlling the nozzle unit to eject the predetermined number of droplets from each of the plurality of cells.

Implementation Method

[0007] Form used to implement the invention

[0008] Generally speaking, when the inkjet head is set to be longer in the direction orthogonal to the scanning direction of printing, the following approach is taken: multiple inkjet heads are combined to form an inkjet head unit. However, since the inkjet head unit becomes longer, it is more prone to extension or skew, resulting in a physical positional deviation from the ideal nozzle position.

[0009] Furthermore, ideally, the nozzle of an inkjet head should eject droplets directly downwards from the nozzle. However, due to the unique angle of the nozzle, there may be deviations in the flight angle of the droplets ejected from the nozzle.

[0010] Deviation of nozzle position and droplet flight angle will cause deviation of droplet landing position (the deviation of the actual landing position from the target landing position). Therefore, in conventional technology, it is difficult to ensure that a specified number of droplets fall in each cell when applying ink to the cells of a display panel. In recent years, with the continuous progress in improving display image quality and narrowing cell pitch, this problem has become even more prominent.

[0011] The purpose of this disclosure is to provide a coating method that allows a specified number of liquid droplets to fall onto a coating target.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Furthermore, the embodiments described below are all embodiments showing preferred specific examples of the present disclosure. Therefore, the values, shapes, materials, constituent elements, arrangement positions of constituent elements, and connection methods shown in the following embodiments are merely examples and are not intended to limit the essence of the present disclosure. Accordingly, among the constituent elements in the following embodiments, those not described in the independent claims representing the highest concept of the present disclosure are described as arbitrary constituent elements. <Inkjet Device>

[0013] First, the configuration of the inkjet device of this embodiment will be explained using FIG1 and FIG2.

[0014] The inkjet device 1 includes: a printhead unit 2 having a plurality of inkjet heads 3 (see Figure 2); and a stage 7 for mounting a panel 8.

[0015] The inkjet apparatus 1 is configured to allow the panel 8 on the stage 7 and the printhead unit 2 to move relative to each other in the scanning direction. During this relative movement, the inkjet apparatus 1 applies ink from the nozzles N formed in the printhead 3 to the cell 81 on the panel 8. For example, the inkjet apparatus 1 is used to apply droplets of ink containing organic functional materials to the cell to form an organic functional layer.

[0016] In this embodiment, a plurality of unit cells 81 are arranged in a configuration direction to form a first unit cell column 82, another plurality of unit cells 81 are arranged in the configuration direction to form a second unit cell column 83, and further, another plurality of unit cells 81 are arranged in the configuration direction to form a third unit cell column 84. The second unit cell column 83 is adjacent to the first unit cell column 82 in the scanning direction. The third unit cell column 84 is adjacent to the second unit cell column 83 in the scanning direction. In this example, the second unit cell column 83 and the third unit cell column 84 are not offset relative to the first unit cell column 82 in the configuration direction. However, the second unit cell column 83 and the third unit cell column 84 may also be offset relative to the first unit cell column 82 in the configuration direction.

[0017] In this embodiment, each unit cell 81 has an elongated oval shape. However, each unit cell 81 may also have a circular, quadrilateral, hexagonal, or other shapes.

[0018] The inkjet device 1 can also use an RGB strip arrangement to coat ink onto the first cell column 82, the second cell column 83 and the third cell column 84, or it can use a PenTile arrangement to coat ink onto the first cell column 82, the second cell column 83 and the third cell column 84.

[0019] Furthermore, this embodiment includes three types of cells for RGB (three types of cells for different inks), and the first cell column 82, the second cell column 83, and the third cell column 84 correspond to RGB respectively. However, it is not limited to this; the panel 8 may contain only one type of cell or may contain multiple types of cells. Furthermore, the cells corresponding to RGB will be referred to below as red cell, green cell, and blue cell.

[0020] On panel 8, cells (color areas) are formed at a predetermined spacing (see CP in Figure 2) in the arrangement direction. In this disclosure, the spacing of cells in the arrangement direction is referred to as "cell pitch CP". -Stage-

[0021] The stage 7 is configured such that it can hold an ink-coating object, namely a panel 8. The stage 7 has a moving mechanism (not shown), which moves the panel 8 in the scanning direction and in an arrangement direction orthogonal to the scanning direction. The moving mechanism of the stage 7 operates, for example, based on a control signal output from the drive control unit described later. The moving mechanism of the stage 7 can employ a configuration already well-known in the past. -Inkjet Unit-

[0022] The upper part of Figure 2 shows an ideal state, that is, an example of the configuration of the printhead unit 2 in the design. The printhead unit 2 has a plurality of inkjet heads 3 arranged in parallel with each other.

[0023] The inkjet head 3 is elongated and each is arranged at a predetermined angle relative to the scanning direction. In each inkjet head 3, a plurality of nozzles N are formed at equal intervals along its long side. Furthermore, the plurality of inkjet heads 3 are arranged such that the spacing between the nozzles N is equal relative to the arrangement direction. The spacing NP between the nozzles in the arrangement direction can be, for example, about 20 μm. Thus, a narrow-pitch printhead unit 2 can be achieved by tilting the inkjet heads 3.

[0024] In this disclosure, as shown in FIG2, the position of a nozzle N ideally configured such that the distance NP between the nozzles is equal is called the "design position of nozzle N". Ideally, the droplets ejected from nozzle N will fall directly below. That is, in an ideal state, the design position of nozzle N and the droplet falling position will be equal in both the arrangement direction and the scanning direction.

[0025] Furthermore, in the following description, for ease of explanation, when explaining each nozzle N separately, the symbols N1, N2, N3, ... will sometimes be attached sequentially from the left side of the diagram. In this case, the same symbols as the nozzles may sometimes be used to indicate the position of each nozzle. In addition, the numerical part of N1, N2, N3, ... excluding N will be referred to as the logical nozzle number of each nozzle N. The same arrangement is made in diagrams other than Figure 2.

[0026] The upper part of Figure 3 shows one example of the configuration (actual state) of the manufactured nozzle unit 2.

[0027] As mentioned above, ideally, the nozzles N are configured to be evenly spaced in the arrangement direction. However, in reality, as shown in the upper part of Figure 3, sometimes a positional deviation occurs between the "designed position of the nozzle N" and the actual nozzle position due to the extension or skewing of the printhead unit 2. This positional deviation is caused by, for example, the following: (1) extension or skewing of individual inkjet heads 3; (2) installation error when mounting the plate (printhead unit 2) that fixes multiple inkjet heads 3; (3) extension or skewing of the fixed position of the inkjet head 3 due to material expansion and contraction caused by heat in the plate that fixes multiple inkjet heads 3. Therefore, the accuracy of the actually assembled nozzle position includes the absolute accuracy error of the plate that mounts the inkjet head and the printhead, as well as the assembly accuracy error during assembly.

[0028] Furthermore, sometimes the flight angle of the droplets ejected from the nozzle N deviates, causing the droplet position to deviate from directly below the nozzle. In fact, each nozzle has its own unique ejection angle when ejecting ink from the nozzle N. Therefore, the ejection position can be determined based on the gap G between the inkjet head 3 and the panel 8 to be coated.

[0029] Figure 4(a) is a view from above showing the droplet positions on the panel 8, which are offset due to the nozzle position of the inkjet head 3 and the unique ejection angle. Figure 4(b) is a view from the side showing the same droplet positions as in Figure 4(a). Furthermore, in Figure 4(a), N1 to N5 represent the designed positions of each nozzle. That is, Figure 4 shows a configuration where each nozzle N1 to N5 is positioned at its designed position. As shown in Figures 4(a) and (b), due to the unique ejection angle, the droplet positions P1 to P5 corresponding to the designed positions N1 to N5 of each nozzle are offset. The feature of the disclosed technology is that even when the droplet positions are offset due to the physical offset of the nozzle N and the 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 Device". -Processing Unit-

[0030] 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, which performs the first position correction processing and the second position correction processing described later. The arithmetic processing unit 4 is implemented, for example, as a microcomputer or CPU (processor) composed of one or more chips. (Drop position calculation unit)

[0031] The drop position calculation unit 41 calculates the positional deviation of each drop position P from the target drop position based on the imaging results of the drop positions 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 downwards from the designed position of each nozzle N. -Memory Unit-

[0032] The memory unit 5 has the function of storing information such as the program used to make the CPU (microcomputer) operate or the processing results of the CPU (microcomputer). In addition, the memory unit 5 has a first region 51, a second region 52 and a third region 53.

[0033] As shown in Figure 7, the drip position deviation data T2 (described later) can be stored in area 1 51. The nozzle configuration arrangement data T1 and the nozzle correction table T3 (described later) can be stored in area 2 52. The printing data T4 and the target coordinate data T5 can be stored in area 3 53.

[0034] Nozzle configuration arrangement data T1 is data that establishes and saves the logical nozzle information and physical nozzle information.

[0035] Logical nozzle information is data about the design position of the nozzles, and it is data that establishes a link between the logical nozzle number and the position information of the nozzle corresponding to each logical nozzle number. An example of nozzle configuration data T1 is shown in the upper left of Figure 8. In the example in Figure 8, the position of nozzle N1, with logical nozzle number "1", is set as the origin (zero point). Figure 8 shows an example of nozzles N being configured with a spacing of 100 μm in the configuration direction.

[0036] The physical nozzle information consists of the printhead number indicating the position of the printhead 3 in the printhead unit 2, and the physical nozzle number indicating the position of the nozzle N in each printhead 3. For example, in Figure 8, as the printhead number in Figure 2, the printhead 3 on the left side of the diagram is sequentially numbered 1, 2, 3, ... . Furthermore, in each printhead 3, the nozzle number is sequentially numbered 1, 2, 3, 4 starting from the nozzle N on the left side of the diagram. For example, for the leftmost nozzle of the printhead 3 on the left side of Figure 2, the physical nozzle number 1 of printhead number 1 is attached in Figure 8, and it is linked to the logical nozzle number 1 (nozzle N1).

[0037] The nozzle configuration arrangement based on physical nozzle information is set as physical nozzle configuration arrangement 35, and the nozzle configuration arrangement based on logical nozzle information is set as logical nozzle configuration arrangement 36.

[0038] Printing data T4 displays the driving state of each of the plurality of nozzles at each of a plurality of time points during the scanning of printhead unit 2. For example, the plurality of time points include: a first time point where the nozzle is located on a red cell, a second time point where the nozzle is located on a green cell, and a third time point where the nozzle is located on a blue cell. The driving state includes a first drive for dispensing ink and a second drive for preventing ink dispensing. For example, the plurality of nozzles includes a red nozzle that dispenses red ink and sequentially passes through red, green, and blue cells during the scanning of printhead unit 2. For this red nozzle, printing data T4 displays the first drive at the first time point, the second drive at the second time point, and the third drive at the third time point.

[0039] Furthermore, a plurality of nozzles are included in the scanning of the printhead unit 2, passing between cells in the arrangement direction without passing through any single cell. For such nozzles, the printed data T4 will display the second drive at any of the first, second, and third time points.

[0040] Furthermore, the so-called second drive to prevent ink ejection means applying voltage to the piezoelectric element until ink is no longer ejected from the nozzle.

[0041] The target coordinate data T5 defines the starting coordinates of the cell configuration, the cell size, and the spacing between cells. Furthermore, multiple sets of target coordinate data T5 can also be prepared. By doing so, it becomes possible to check the number of nozzles allocated to all cells for multiple target cell positions.

[0042] Furthermore, the memory unit 5 (memory) can be housed within the same chip as the processing unit 4, or it can be separated from the processing unit 4 and housed as a separate chip. Alternatively, the memory unit 5 can be implemented using memory media such as HDD (Hard Disk Drive) or SSD (Solid State Drive). -Drive Control Unit-

[0043] The drive control unit 6 has the following functions: in a series of actions in which the inkjet head 3 scans relative to the panel 8 while ejecting ink, it moves the stage on which the panel 8 is mounted or controls the drive of the nozzle N. The drive control unit 6 is implemented, for example, as a microcomputer or CPU (processor) composed of one or more chips.

[0044] Specifically, the drive control unit 6 reads the printing data T4 from the memory unit 5 and outputs the drive waveform received from the drive waveform signal generator (not shown) to each nozzle N of the inkjet head 3 according to the printing data T4. For example, when the printing data T4 shows the first drive for a certain nozzle at a certain time point, the drive control unit 6 supplies the drive waveform for ink ejection to that nozzle at that time point. When the printing data T4 shows the second drive for that nozzle at another time point, the drive control unit 6 supplies the drive waveform for preventing ink ejection to that nozzle at that time point.

[0045] Furthermore, the drive control unit 6 has the function of moving the panel 8 or the nozzle unit 2 in the arrangement direction according to the first nozzle movement amount or the second nozzle movement amount described later.

[0046] Furthermore, the drive control unit 6 can also be divided into a module for driving control of the shaft (stage, etc.) system and a module for driving control of the printhead ejection. <Coating Method Using an Inkjet Device>

[0047] Hereinafter, with reference to Figures 3, 5, 6, and 7, a coating method using the inkjet apparatus 1 will be specifically described. The method described here involves coating each of the aforementioned cell 81, which is already set on the panel 8, with a predetermined number of droplets using nozzles N. Although the nozzles N are designed to be configured with a nozzle spacing NP, they are actually offset in position. This coating method includes an observation step, a generation step, a printing data generation step, and a coating step. This coating method can also be implemented wholly or partially by a computer, which has a processor and memory storing programs that can be executed by this processor. For example, as described above, the processor can also be included in the arithmetic processing unit 4 and the drive control unit 6. The memory can also be, for example, a memory unit 5. -Observation Step-

[0048] In the observation step, the deviation of the droplet landing position of the liquid ejected from each nozzle is observed.

[0049] Specifically, in step F1 of FIG5, printing data is generated (FIG. 7 F10), and a pattern for detecting the drop position (hereinafter referred to as the drop pattern) is printed (FIG. 7 F11). When printing the drop pattern, it is formed such that more than one droplet is ejected from each nozzle N.

[0050] In the next step F2, a drop observation camera (not shown) is used to observe the drop pattern printed in step F1 (Fig. 7, F21). The drop position calculation unit 41 calculates the positional deviation of the drop pattern from the target drop position based on the camera's shooting results (Fig. 7, F22).

[0051] At this time, as shown in FIG4(a), the positional deviation between the scanning direction and the arrangement direction can be observed. In this embodiment, at least the information on the drop position deviation in the arrangement direction (hereinafter referred to as "drop position deviation data T2") is calculated, and the drop position deviation data T2 is used. That is, in the following case, when simply referred to as "drop position deviation data T2", it means the information on the drop position deviation in the arrangement direction. An example of drop position deviation data T2 is shown in the lower left of FIG8.

[0052] Furthermore, the deviation of the droplet position in the scanning direction can be resolved, for example, by adjusting the ink ejection timing from each nozzle N. The acquired droplet position deviation data T2 can be stored in the first region 51 of the memory unit 5. -Generation Step-

[0053] In the generation step, the driving nozzle to be driven is selected based on the nozzle configuration arrangement data T1 and the drop position deviation data T2, and the configuration arrangement data of the driving nozzle, i.e., the replacement configuration arrangement data (updating configuration arrangement data), is generated.

[0054] The following describes the specific generation process with reference to Figures 5 and 6.

[0055] First, in step F3 of Figure 5, a position correction process (hereinafter referred to as the first position correction process) is performed. The aforementioned position correction process optimizes the nozzle configuration data based on the aforementioned nozzle arrangement data T1 and the drop position deviation data T2 calculated in step F2. (First Position Correction Process)

[0056] Figure 6 is a flowchart showing the details of the first position correction process (equivalent to the first search step).

[0057] First, in step F31, based on the nozzle configuration arrangement data T1 and the drop position deviation data T2, a reordering process is performed on the nozzles N according to the accuracy guarantee distance of each nozzle N in the configuration arrangement direction. In this reordering, the accuracy guarantee distance must be set according to the required accuracy for the printing object. The nozzle correction table T3 in Figure 8 shows the result of the above reordering performed with the accuracy guarantee distance set to 0.045mm.

[0058] As a specific process, a nozzle correction table T3 is generated by selecting nozzles N whose droplet positions are within the accuracy guarantee distance range relative to the design positions of each nozzle N and re-establishing the connection. More specifically, nozzles whose ejected droplets fall within the following range: the range from the target droplet position corresponding to the design position of nozzle N to the accuracy guarantee distance. If such a nozzle can be found, the found nozzle is selected as the driving nozzle corresponding to the design position of nozzle N. If no nozzle can be found, no nozzle is selected as the driving nozzle corresponding to the design position of nozzle N. If there are two or more physical nozzles within the accuracy guarantee distance range of a design position of nozzle N, the physical nozzle closest to the design position of nozzle N is selected and a connection is established. Furthermore, physical nozzles that are not selected are set as nozzles that do not eject droplets, i.e., "non-ejecting nozzles".

[0059] For example, in the example of the drip position deviation data T2 in Figure 8, the drip positions of nozzles N4 and N7 relative to their designed nozzle positions deviate by more than the accuracy guarantee distance, i.e., 0.045 mm. Therefore, nozzles N4 and N7 cannot be assigned as drive nozzles in their respective designed positions. Secondly, regarding the designed position of nozzle N5, when comparing the drip position P4 of nozzle N4 with 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 in the designed position of nozzle N5. Furthermore, nozzles N with logical nozzle numbers "5" and "7" that are not assigned as drive nozzles are set as non-discharge nozzles.

[0060] In the next step F32, updated nozzle information Z6 is generated. Updated nozzle information Z6 includes: updated configuration arrangement data T6 based on nozzle configuration arrangement data T1, and updated position deviation data T7 based on drop position deviation data T2.

[0061] Specifically, the updated configuration arrangement data T6 is the updated data of the connection between the logical nozzles and physical nozzles in the nozzle configuration arrangement data T1, corresponding to the updated new nozzle positions shown in the nozzle correction table T3 above. The updated position deviation data T7 is the updated data of the drip position deviation data T2, corresponding to the updated new nozzle positions shown in the nozzle correction table T3.

[0062] In the next step F33, the movement amount of the first nozzle is calculated. The movement amount of the first nozzle is the offset movement amount in the overall configuration direction of the nozzle unit 2. This offset movement amount is set to minimize the number of nozzles that are not connected, i.e., nozzles that do not eject, during the nozzle N reordering process in the aforementioned step F31. Specifically, the following process is performed: searching for the optimal offset movement amount within any specified range and specified spacing.

[0063] For example, taking the example in Figure 8, it is advisable to set -0.02mm as the movement amount of the first nozzle. In this way, the drop position deviation of nozzle N1 is updated from +0.03mm to +0.01mm. Similarly, the drop position deviations of nozzles N2 to N7 are updated to -0.04mm, -0.01mm, +0.045mm, +0.02mm, and +0.07mm, respectively. Thus, the drop position deviation of nozzle N4 is changed from +0.065mm to +0.045mm. In this way, since the aforementioned accuracy guarantee distance is met, nozzle N4 can be assigned to the design position of logical nozzle number "4". In addition, nozzle N5 can be assigned to the design position of logical nozzle number "5". On the other hand, in logical nozzle number "7", no nozzle is then assigned as a driving nozzle. Thus, in the example of Figure 8, by setting the first nozzle movement to -0.02mm, one more drive nozzle can be added compared to the previous setting. This is used to calculate the minimum first nozzle movement if no nozzle is ejected.

[0064] After the processing is completed, return to Figure 5 and proceed to the next step F4.

[0065] In step F4, the nozzle correction table T3 is updated to include the data of the first nozzle movement calculated in step F33. Furthermore, in conjunction with the update of the nozzle correction table T3, the updated configuration arrangement data T6 and the updated position deviation data T7 are updated again.

[0066] In the next step F5, the validity / invalidity of the optimization process is determined. The determination of whether optimization is needed (whether to make it valid) can also be based on, for example, whether a predetermined number of droplets can be ejected from each unit cell.

[0067] If the nozzle optimization process in step F5 is invalid, the first printhead movement amount can be set to the inkjet device 1 as the printhead movement amount (step F6). Furthermore, if the process in step F6 is completed, the process proceeds to the next step F9 (print data generation step). The print data generation step will be explained later.

[0068] On the other hand, when the nozzle optimization process in step F5 is effective, from the viewpoint of ensuring a greater number of droplets per unit cell 81, a position correction process (hereinafter referred to as the second position correction process) is performed to optimize the nozzle unit 2 by adding an offset movement amount in the configuration arrangement direction. In the second position correction process, a process is performed to search for the optimal offset movement amount, which is the offset movement amount that can ensure a greater number of droplets per unit cell 81 within any specified range and spacing. (Second Position Correction Process)

[0069] Figures 10 and 11 are used to illustrate a specific example of the second position correction process (equivalent to the second search step).

[0070] Figure 10 shows the nozzles N assigned to the cells when printed to the panel 8 according to the design values, and shows the positions of the nozzles in the design with ideal configuration. In Figure 10, as shown by the shaded lines, ideally, it is configured such that up to 3 drops can be dropped onto each cell 81.

[0071] In contrast, Figure 11 shows examples of nozzle N being misaligned and nozzles not ejecting ink. A nozzle not ejecting ink refers to a nozzle that is not used on a printed material due to nozzle misalignment or other reasons (a nozzle that does not eject any of the R, G, or B inks even once). In Figure 11, nozzles N5, N13, N20, N25, N31, and N38 are shown as non-ejecting nozzles, indicated by dashed lines. Furthermore, Figure 11 is considered to be a case where there is no deviation in the drip position caused by the specific ejection angle of nozzle N.

[0072] An example where the second position correction process was not performed is shown in the upper part of Figure 11. In this example, in the sixth cell 81 from the left, due to the effect of the non-discharge nozzle and positional deviation, the number of droplets falling into cell 81 will be 2. From the viewpoint of achieving a uniform film thickness of R, G, and B within the cell, the droplets should be coated uniformly. Therefore, the number of droplets is set according to the cell with the fewest droplets among all cells. As a result, in Figure 11, the number of droplets that can be dispensed in one operation for all cells will be 2, and it becomes impossible to ensure a sufficient number of droplets.

[0073] Therefore, a second position correction process is performed to search for the optimal offset movement amount. The aforementioned optimal offset movement amount is the offset movement amount that can ensure a greater number of droplets for each cell 81 within a predetermined search range and a predetermined search interval. Here, the calculated offset amount is referred to as the "second nozzle movement amount". In this embodiment, ensuring the number of droplets for each cell 81 based on the second nozzle movement amount is given priority over minimizing the non-discharge nozzle based on the first nozzle movement amount.

[0074] Specifically, for example, the "search range" is set to -15μm to 15μm, and the "search interval" is set to 5μm.

[0075] In this way, in addition to the first nozzle movement amount calculated in step F33, the nozzle unit 2 is also displaced by -15μm, -10μm, -5μm, 0μm, 5μm, 10μm, and 15μm, and the distribution state of the number of droplets to each cell 81 at each position is calculated. For example, when the second nozzle movement amount is set to -10μm, the state shown in the lower part of FIG11 is obtained. In this way, by applying the calculated second nozzle movement amount (-10μm), the number of droplets uniformly ejected into each cell in one coating operation can be formed to a maximum of 3 drops. Furthermore, if there is no other offset movement amount that can achieve a droplet count of more than 3 drops in all cells 81, -10μm can be set as the second nozzle movement amount.

[0076] Furthermore, although an example of performing a second position correction process with the aim of increasing the maximum number of droplets that can be ejected into each unit cell has been shown here, it is not limited to this. For example, as a second position correction process, the offset movement can also be determined by placing the droplets from each nozzle closer to the center of the unit cell. In this case, the same operation as described above can be performed. If it is desired to further improve the alignment accuracy, the search spacing can be set to be narrower. In this way, the generation of defective products caused by droplets flying out of unit cell 81 can be more reliably prevented.

[0077] Furthermore, in the above description, it is also possible to consider reducing the maximum number of drops that can be dispensed from 3 drops to 2 drops by not dispensing nozzles. Also, it can be set that if the number of droplets allocated to the cell is still less than the predetermined number even though the entire search range has been searched, it is determined that printing is not possible, and an error notification is sent to the external device (illustration omitted).

[0078] If the calculation of the second printhead movement is completed, then in the next step F8, the inkjet unit 1 is set to "first printhead movement + second printhead movement" as the printhead movement amount. Furthermore, if the processing in step F8 is completed, the process proceeds to the next step F9 (print data generation step). -Print Data Generation Step-

[0079] In step F9, the printing data generation step, printing data is generated using the configuration and arrangement data of the drive nozzles, i.e., the replacement configuration and arrangement data. Regarding the specific method for generating printing data, since conventionally known methods can be applied, a detailed description is omitted here. If the printing data generation step is completed, the next step F10 (coating step) is initiated. The printing data is generated based on the amount of nozzle movement calculated from the amount of movement of the nozzle unit 2 in the configuration and arrangement direction. For example, if the nozzle movement is only the first nozzle movement, the printing data is generated based on the amount of movement of the nozzle unit 2 in the configuration and arrangement direction equivalent to the first nozzle movement. If the nozzle movement is the sum of the first and second nozzle movements, the printing data is generated based on the amount of movement of the nozzle unit 2 in the configuration and arrangement direction equivalent to the sum of the first and second nozzle movements. -Coating Step-

[0080] In the coating step of step F10, the print data generated in the print data generation step is used to control the print head unit 2 to eject a predetermined number of droplets onto each cell 81. Specifically, for example, the drive control unit 6 reads the print data based on the displacement configuration arrangement data from the memory unit 5, and outputs the drive waveform received from the drive waveform signal generator (not shown) to each nozzle N of the inkjet head 3 according to the print data.

[0081] As described above, by using the coating method of this embodiment, an optimal nozzle distribution state can be created for the unit cell 81 to which the coating is to be applied. Specifically, as shown in FIG9, in the case where the nozzle distribution state is not corrected (comparative example), only one droplet can be ensured in the unit cell at the center of the figure. In contrast, by using the coating method of this embodiment, as shown in FIG3, two droplets can be applied near the center of the unit cell.

[0082] Furthermore, according to this embodiment, by using the first nozzle movement amount and moving the nozzle unit, an optimal nozzle allocation state for the cell to be printed can be created. Furthermore, by using a second nozzle movement amount in addition to the first nozzle movement amount and moving the nozzle unit, the number of droplets that can be coated within the cell can be increased, or the ink droplet positions can be aligned. Moreover, the nozzle unit can also be moved solely based on the second nozzle movement amount without performing movement based on the first nozzle movement amount. <Other Embodiments>

[0083] Furthermore, this disclosure is not limited to the description of the above-described embodiments, and various modifications can be made without departing from its main theme.

[0084] For example, in the above embodiment, although the inkjet heads 3 are arranged at a predetermined angle relative to the scanning direction, this is not a limitation. For example, as shown in FIG12, the inkjet heads 3 extending in the arrangement direction can also be arranged in the scanning direction. In this case, the positions of each inkjet head 3 in the arrangement direction are offset from the distance NP between the nozzles. In this way, the distance NP between the nozzles can be made narrower.

[0085] Furthermore, Figure 13 shows a diagram equivalent to Figure 3. In this case, the same effect can still be obtained by performing the same process as the aforementioned "coating method using an inkjet device".

[0086] Furthermore, as shown in FIG14, the configuration of FIG12 can also be used, in which the inkjet heads 3 are each tilted at a predetermined angle relative to the scanning direction. Also, as shown in FIG15, the configuration of FIG14 can be set as a single unit, and arranged staggered in both the scanning direction and the arrangement direction. In FIG14 and FIG15, the same effect can still be obtained by performing the same process as the aforementioned "coating method using an inkjet apparatus".

[0087] In the above embodiment, the nozzle N is reordered according to the accuracy of the distance between each nozzle N in the arrangement direction (F31 of FIG6). However, this disclosure is not limited to this, and the nozzle N reordering process may not be performed.

[0088] For example, as shown in FIG16, such a coating method includes the following steps: printing a pattern for detecting the drop position (step F51); and detecting the deviation of the drop position from the designed position (step F52). Since steps F51 and F52 are the same as steps F1 and F2 (see FIG5), detailed descriptions are omitted.

[0089] The coating method of this modified example further includes the following steps: calculating the amount of nozzle movement in the arrangement direction of the nozzle unit 2 based on the deviation of each nozzle from the designed drop position (step F53). The amount of nozzle movement can also be calculated, for example, in a way that minimizes the number of nozzles that do not eject, or in a way that allows the desired number of droplets to be ejected from each cell.

[0090] The coating method of this modified example further includes the following step: generating printing data while the nozzle unit 2 has moved by an amount equivalent to the calculated nozzle movement (step F54). Since step F54 is the same as step F9 (see Figure 5), detailed description is omitted.

[0091] The coating method of this modified example further includes the following step: adjusting the position of the nozzle unit 2 in the arrangement direction (step F55). Specifically, the nozzle unit 2 is moved relative to the stage 7 in the arrangement direction by an amount equivalent to the nozzle movement. Step F55 may be performed before or after step F54.

[0092] The coating method of this modified example further includes a coating step (step F56). Since step F56 is the same as step F10, detailed description is omitted.

[0093] As described above, the coating method of the above-described modified example uses a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing. The nozzle unit coats a predetermined number of droplets on each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on the object to be coated. The coating method includes the following steps: (a) observing the deviation of the droplets ejected from each of the nozzles from the droplet position in the configuration direction relative to the target droplet position pre-set for each of the nozzles; (b) searching for a second nozzle movement amount, the second nozzle movement amount being the amount of offset movement of the nozzle unit in the configuration direction based on the droplet position deviation of the droplets ejected from each of the nozzles in the configuration direction, so that the number of droplets coated on each of the cells becomes a predetermined number of droplets; (c) Displace the aforementioned nozzle unit in the aforementioned configuration direction by an amount equivalent to the movement of the aforementioned second nozzle; and (d) Control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets from each of the aforementioned plurality of unit cells.

[0094] Alternatively, the coating method of the above-described modified example uses a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing. The nozzle unit coats a predetermined number of droplets on each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on the object to be coated. The coating method includes the following steps: (a) observing the deviation of the droplets ejected from each of the nozzles from the droplet position in the configuration direction relative to the target droplet position pre-set for each of the nozzles; (b) classifying the plurality of nozzles into used nozzles that pass through the plurality of cells and unused nozzles that do not pass through the plurality of cells; (c) searching for a first nozzle movement amount based on the droplet position deviation of the droplets ejected from each of the nozzles in the configuration direction. The first nozzle movement amount is the offset movement amount of the nozzle unit in the configuration direction before the number of unused nozzles is minimized. (d) Displace the aforementioned nozzle unit in the aforementioned configuration direction by an amount equivalent to the movement of the aforementioned first nozzle; and (e) Control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets from each of the aforementioned plurality of unit cells.

[0095] According to the coating method of this disclosure, a specified number of droplets can be dropped onto the target object. Industrial applicability.

[0096] As explained above, the coating method disclosed herein is effective for applying ink or the like to printed objects at fixed intervals with high precision, even when the nozzle position within the inkjet head cannot be changed. It is particularly suitable for inkjet printing apparatuses used in printing organic EL light emitters, hole transport layers, electron transport layers, color filters, or for forming uniform films, and has high industrial applicability. [Simplified Explanation of the Diagram]

[0006] Figure 1 is a schematic diagram showing an example of the configuration of an inkjet device. Figure 2 is a diagram showing an example of the nozzle position in the design state of the printhead unit. Figure 3 is a diagram showing an example of the nozzle position of the manufactured printhead unit. Figure 4 is a diagram illustrating the positional deviation caused by the unique ejection angle of the nozzle. Figure 5 is a flowchart showing the processing flow of the coating method of this embodiment. Figure 6 is a flowchart showing the processing flow of the first position correction process. Figure 7 is a diagram showing the data processing flow of the coating method of this embodiment. Figure 8 is a diagram showing an example of the data processing method for each table. Figure 9 is a diagram showing an example of the nozzle position of the printhead unit in a comparative example. Figure 10 is a diagram showing the nozzles allocated to the cell when printing on the workpiece according to the design values. Figure 11 is a diagram showing an example of nozzles with positional deviation and unusable nozzles in Figure 10. Figure 12 is a diagram corresponding to Figure 2 with respect to a modified example. Figure 13 is a diagram corresponding to Figure 3 with respect to a modified example. Figure 14 is a diagram showing another example of the nozzle position in the designed state of the spray head unit. Figure 15 is a diagram showing another example of the nozzle position in the designed state of the spray head unit. Figure 16 is a flowchart showing the processing flow of the coating method in a modified example.

Claims

1. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, wherein the nozzle unit coats a predetermined number of droplets on each of the plurality of cells arranged in the configuration direction at a predetermined cell spacing on a coating object, the coating method comprising the following steps: an observation step, observing the deviation of droplets ejected from each of the nozzles from a drop position in the configuration direction relative to a target drop position pre-set for each of the nozzles; The generation step involves selecting nozzles whose drop positions are within the accuracy guarantee distance range from the plurality of nozzles, based on the design position data of each nozzle and the deviation data of the drop position for each nozzle, as driving nozzles to be driven, and selecting nozzles whose drop positions are outside the aforementioned accuracy guarantee distance range as non-dispensing nozzles, and generating configuration arrangement data for the aforementioned driving nozzles, namely displacement configuration arrangement data; and the coating step involves using the aforementioned displacement configuration arrangement data to control the aforementioned nozzle unit to dispense the aforementioned predetermined number of droplets to each of the aforementioned plurality of unit cells.

2. The coating method of claim 1 further includes the following steps: a printing data generation step, which uses the aforementioned displacement configuration arrangement data to generate printing data, and the aforementioned coating step uses the aforementioned printing data to control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets onto each of the aforementioned plurality of unit cells.

3. The coating method of claim 2 further includes a first search step, which uses the aforementioned displacement configuration data to search for a first nozzle movement amount, wherein the aforementioned first nozzle movement amount is the offset movement amount of the aforementioned nozzle unit in the aforementioned configuration direction when the number of non-ejecting nozzles not selected as driving nozzles among the aforementioned plurality of nozzles is at least a certain amount, and in the aforementioned printing data generation step, the aforementioned printing data is generated in a state where the aforementioned nozzle unit has been displaced in the aforementioned configuration direction by the aforementioned first nozzle movement amount.

4. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, the nozzle unit coating each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on a coating object with a predetermined number of droplets, the coating method comprising the steps of: an observation step, observing the deviation of droplets ejected from each of the nozzles from a droplet position in the configuration direction relative to a pre-set target droplet position for each of the nozzles; a generation step, selecting a driving nozzle from the plurality of nozzles as the driving object based on design position data of each nozzle and data on the aforementioned droplet position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., displacement configuration data; and a coating step, using the aforementioned displacement configuration data, controlling the nozzle unit to eject the predetermined number of droplets from each of the plurality of cells, the coating method further comprising the step of: a printing data generation step, using the aforementioned displacement configuration data to generate printing data. The aforementioned coating step uses the aforementioned printing data to control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets onto each of the aforementioned plurality of unit cells. The aforementioned coating method further includes the following steps: a second search step, using the aforementioned displacement configuration data to search for a second nozzle movement amount, wherein the aforementioned second nozzle movement amount is the amount of displacement movement of the aforementioned nozzle unit toward the aforementioned configuration direction before the number of droplets coated on each of the aforementioned unit cells is maximized. In the aforementioned printing data generation step, the aforementioned printing data is generated in a state where the aforementioned nozzle unit has been displaced toward the aforementioned configuration direction by the aforementioned second nozzle movement amount.

5. The coating method of claim 4 further comprises the following steps: a first search step, using the aforementioned displacement configuration arrangement data to search for a first nozzle movement amount, wherein the aforementioned first nozzle movement amount is the offset movement amount of the aforementioned nozzle unit in the aforementioned configuration arrangement direction when the number of non-ejecting nozzles not selected as driving nozzles among the aforementioned plurality of nozzles is at least a certain amount; in the aforementioned printing data generation step, the aforementioned printing data is generated in a state where the aforementioned nozzle unit has been displaced in the aforementioned configuration arrangement direction by the sum of the aforementioned first nozzle movement amount and the aforementioned second nozzle movement amount.

6. The coating method of claim 5, wherein the aforementioned second nozzle movement is achieved by moving the stage on which the aforementioned object to be coated is placed.

7. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, the nozzle unit coating each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on a coating object with a predetermined number of droplets, the coating method comprising the following steps: an observation step, observing the deviation of droplets ejected from each of the nozzles from a droplet position in the configuration direction relative to a pre-set target droplet position for each of the nozzles; a generation step, selecting a driving nozzle from the plurality of nozzles as the driving object based on design position data of each nozzle and data on the aforementioned droplet position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., displacement configuration data; and a coating step, using the aforementioned displacement configuration data, controlling the nozzle unit to eject the predetermined number of droplets from each of the plurality of cells. In the aforementioned observation step, the aforementioned drop position deviation is observed. If the observation result is that there are multiple nozzles that meet the accuracy guarantee distance relative to the design position of the aforementioned nozzle, in the aforementioned generation step, the nozzle closest to the design position of the aforementioned nozzle is selected as the aforementioned driving nozzle.

8. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, the nozzle unit coating each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on a coating object with a predetermined number of droplets, the coating method comprising the steps of: an observation step, observing the deviation of droplets ejected from each of the nozzles from a droplet position in the configuration direction relative to a pre-set target droplet position for each of the nozzles; a generation step, selecting a driving nozzle from the plurality of nozzles as the driving object based on design position data of each nozzle and data on the aforementioned droplet position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., displacement configuration data; and a coating step, using the aforementioned displacement configuration data, controlling the nozzle unit to eject the predetermined number of droplets from each of the plurality of cells, the coating method further comprising the step of: a printing data generation step, using the aforementioned displacement configuration data to generate printing data. The aforementioned coating step uses the aforementioned printing data to control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets onto each of the aforementioned plurality of unit cells. The aforementioned coating method further includes the following steps: a first search step, using the aforementioned displacement configuration data to search for a first nozzle movement amount, wherein the aforementioned first nozzle movement amount is the amount of offset movement of the aforementioned nozzle unit toward the aforementioned configuration direction before the number of non-ejecting nozzles not selected as driving nozzles among the aforementioned plurality of nozzles is at least. In the aforementioned printing data generation step, the aforementioned printing data is generated in a state where the aforementioned nozzle unit has been displaced toward the aforementioned configuration direction by the aforementioned first nozzle movement amount.

9. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, the nozzle unit coating each of the plurality of cells arranged in the configuration direction with a predetermined cell spacing on a coating object with a predetermined number of droplets, the coating method comprising the steps of: an observation step, observing the deviation of droplets ejected from each of the nozzles from a droplet position in the configuration direction relative to a target droplet position pre-set for each of the nozzles; a generation step, selecting a driving nozzle from the plurality of nozzles as the driving object based on design position data of each nozzle and data on the aforementioned droplet position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., displacement configuration data; and a coating step, using the aforementioned displacement configuration data, controlling the nozzle unit to eject the predetermined number of droplets from each of the plurality of cells, the generation step comprising the following steps: The system searches for nozzles from which the ejected droplets fall within the following range: within a distance from the target droplet position corresponding to the designed position of the aforementioned nozzle to ensure accuracy; if the aforementioned nozzle can be found, the searched nozzle is selected as the drive nozzle corresponding to the designed position of the aforementioned nozzle; and if the aforementioned nozzle cannot be found, no nozzle is selected as the drive nozzle corresponding to the designed position of the aforementioned nozzle.

10. A coating method using a nozzle unit having a plurality of nozzles arranged in a configuration direction orthogonal to the scanning direction of printing, wherein the nozzle unit coats a predetermined number of droplets on each of the plurality of cells arranged in the configuration direction at a predetermined cell spacing on a coating object, the coating method comprising the following steps: an observation step, observing the deviation of droplets ejected from each of the nozzles from a droplet position in the configuration direction relative to a target droplet position pre-set for each of the nozzles; and a generation step, selecting a driving nozzle from the plurality of nozzles as the driving object based on design position data of each nozzle and data on the aforementioned droplet position deviation for each nozzle, and generating configuration data of the driving nozzle, i.e., replacement configuration data. The coating step uses the aforementioned displacement configuration arrangement data to control the aforementioned nozzle unit to eject the aforementioned predetermined number of droplets onto each of the aforementioned plurality of unit cells; and the update data generation step, after the aforementioned generation step, generates, in a manner corresponding to the aforementioned displacement configuration arrangement data: logical nozzle information displaying the design position of the nozzle, updated arrangement data updated by linking and updating the physical nozzle information displaying the configuration of the nozzles of the aforementioned nozzle unit, and updated position deviation data based on the aforementioned droplet position deviation data.

Images