How to Compensate for Film Thickness Uniformity in OLED Inkjet Printing

Abstract

The present application relates to the technical field of OLED, and in particular to a method for compensating for thickness uniformity in OLED inkjet printing, which includes: obtaining a target thickness of the OLED, mesh parameters of pixel grooves, and parameters related to ink droplets of each inkjet head in an inkjet device; calculating an inkjet volume and distribution of ink droplets in each pixel groove based on the target thickness, mesh parameters, and parameters related to ink droplets; inkjetting each pixel groove based on the inkjet volume and distribution in each pixel groove; baking each pixel groove to obtain a thickness of each mesh in each baked pixel groove; determining a compensation inkjet volume of each mesh in each pixel groove based on the thickness of each mesh in each pixel groove and the target thickness; and inkjetting each mesh in each pixel groove according to the compensation inkjet volume until the thickness of each pixel groove reaches the target thickness. Using this method, the thickness uniformity of the OLED can be improved.

Description

Related Applications

[0001] This application claims priority to a Chinese patent application filed on February 6, 2023 with the State Intellectual Property Office of the People's Republic of China, bearing application number 202310064695.9 and titled "Method for compensating film thickness uniformity in OLED inkjet printing", and a Chinese patent application filed on November 2, 2022 with the State Intellectual Property Office of the People's Republic of China, bearing application number 202211364103.7 and titled "Ink droplet printing method, apparatus, system and storage medium", the entire contents of which are incorporated herein by reference. [Technical field]

[0002] This application relates to the field of OLED technology, and in particular to a method for compensating for film thickness uniformity in OLED inkjet printing. [Background technology]

[0003] OLED, as a current-type light-emitting device, is increasingly being applied to high-performance displays. Because of its self-luminous properties, AMOLED has many advantages over LCD, such as high contrast ratio, ultra-thin and flexible.

[0004] In the OLED printing process, the OLED material and the ink as the solvent are first printed into the pixel groove of the TFT substrate by the inkjet head using an inkjet device, and the ink is in a solution state. Then, through the VCD (vacuum drying) and bake process, the solvent in the ink is volatilized and removed, leaving the OLED material to be formed into the pixel groove. The volume and distribution of the ink droplets that the inkjet device sprays into the pixel groove directly affect the film thickness uniformity and film formation effect, and also affect the quality of light emission. Summary of the Invention [Problem to be solved by the invention]

[0005] In order to solve the problem of non-uniform film thickness in pixel grooves caused by OLED inkjet printing, the conventional technology mainly improved the printing process flow such as inkjet process, drying and baking. However, it is difficult to precisely control the drying process in the pixel level area, which easily leads to non-uniform film thickness in pixel grooves. [Means for solving the problem]

[0006] According to embodiments of the present application, a method for compensating for film thickness uniformity in OLED inkjet printing is provided.

[0007] In a first aspect, the present application provides a method for compensating for film thickness uniformity in OLED inkjet printing, the method comprising: Obtaining a target film thickness of the OLED, a mesh parameter of a pixel groove, and a parameter related to ink droplets of each inkjet head in an inkjet device, and calculating an inkjet volume and a distribution state of the ink droplets in each pixel groove according to the target film thickness, the mesh parameter, and the parameter related to ink droplets; performing ink jetting for each pixel groove based on the ink jet volume and distribution status within each pixel groove; performing a baking process on each pixel groove and acquiring a film thickness of each mesh in each baked pixel groove; determining a compensation inkjet volume for each mesh in each pixel groove based on the film thickness of each mesh in each pixel groove and the target film thickness, and inkjetting each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness.

[0008] In a second aspect, the present application further provides an apparatus for compensating for film thickness uniformity in OLED inkjet printing, the apparatus comprising: an acquisition module for acquiring a target thickness of the OLED, a mesh parameter of a pixel groove, and a parameter related to ink droplets of each inkjet head in an inkjet device, and calculating an inkjet volume and distribution status of the ink droplets in each pixel groove according to the target thickness, the mesh parameter, and the parameter related to ink droplets; an inkjet module for inkjetting each pixel groove based on the inkjet volume and distribution in each pixel groove; a film thickness acquisition module for performing a baking process on each pixel groove and acquiring a film thickness of each mesh in each baked pixel groove; and a refill module for determining a compensation inkjet volume for each mesh in each pixel groove based on the film thickness of each mesh in each pixel groove and the target film thickness, and inkjetting each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness.

[0009] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the computer program, when executed by the processor, performs the steps of the method for compensating for film thickness uniformity in OLED inkjet printing according to the first aspect.

[0010] In a fourth aspect, the present application further provides a computer readable storage medium having a computer program stored thereon, the computer program being executed by a processor to perform the steps of the method for compensating for film thickness uniformity in OLED inkjet printing according to the first aspect.

[0011] In a fifth aspect, the present application further provides a computer program product, comprising a computer program which, when executed by a processor, performs the steps of the method for compensating for film thickness uniformity in OLED inkjet printing according to the first aspect.

[0012] The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the application will become apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0013] In order to more clearly describe and explain the embodiments and / or examples of the invention disclosed herein, reference may be made to one or more drawings. Any descriptions or illustrations added to illustrate the drawings should not be construed as limiting the scope of the disclosed invention, the described embodiments and / or examples, or any of the best modes of the invention as understood. [Figure 1] FIG. 1 is a schematic diagram showing an application environment of a method for compensating for film thickness uniformity in OLED inkjet printing in one embodiment; [Diagram 2] 1 is a schematic flow chart of a method for compensating film thickness uniformity in OLED inkjet printing in one embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing pixel groove meshing in an embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a combination of ink droplets in one embodiment. [Diagram 5] FIG. 4 is a schematic diagram showing penetration of ink droplets in an embodiment. [Figure 6] FIG. 13 is a schematic diagram showing a more detailed flow of the step of calculating the inkjet volume and distribution status of the ink droplets in each pixel groove based on the target film thickness, mesh parameters, and ink droplet-related parameters in one embodiment. [Figure 7] FIG. 2 is a schematic diagram showing classification of pixel grooves in an embodiment. [Figure 8] FIG. 1 is a block diagram showing the configuration of an apparatus for compensating for film thickness uniformity in OLED inkjet printing in one embodiment. [Figure 9] FIG. 2 is a diagram illustrating the internal configuration of a computer device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] It should be understood that the specific embodiments described herein are merely for purposes of illustrating the present application, and are not intended to limit the present application.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used herein are for the purpose of describing specific examples only and are not intended to limit the present application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the description of the drawings above are intended to cover non-exclusive inclusions.

[0016] It should be noted that when an element is referred to as "anchored" to another element, it may be directly connected to the other element or there may be intervening elements. It should be noted that when an element is referred to as "connected" to another element, it may be directly connected to the other element or there may be intervening elements. Terms such as "vertical", "horizontal", "left", "right", etc., as used herein are for descriptive purposes only.

[0017] In the drawings, the sizes of layers and regions may be exaggerated for clarity of illustration. It is also understood that when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on the other layer or substrate, or that there may be one or more intervening layers. It is also understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or that there may be one or more intervening layers. Additionally, like reference numbers refer to like elements throughout.

[0018] In the following examples, when a layer, region, or element is referred to as being "connected," this can be interpreted to mean that the layer, region, or element is not only directly connected, but also connected via another intervening component. For example, when a layer, region, element, etc. is described as being connected or electrically connected, the layer, region, element, etc. may not only be directly connected or electrically connected, but may also be connected or electrically connected via another intervening layer, region, element, etc.

[0019] It is further understood that terms such as "comprise" or "have" specify the presence of stated features, integers, steps, operations, components, portions, or groups thereof, but do not exclude the presence or possibility of one or more other features, integers, steps, operations, components, portions, or groups thereof.

[0020] One of the prior art techniques changes the evaporation speed of the solvent by improving the condensation plate, and solves the problem of non-uniform film thickness caused by the fast air flow at the edge of the substrate and the different evaporation speed of the ink. Although this method solves the problem of non-uniform film thickness during the drying process to some extent, in the actual drying process, it is necessary to precisely control the temperature, flow rate and pressure of the gas, and furthermore, it is necessary to ensure that the solvent in the ink evaporates and does not cause physical distortion to the luminescent material remaining in the pixel groove, which places high requirements on the precision of the component devices and increases the difficulty of designing the solution.

[0021] Another prior art is to improve the cross section of the heat source beam generated by the inkjet head of the dried ink, so that the solidification speed of the ink in the middle area of ​​the pixel groove of the target substrate is faster than that of the edge area. However, although this method is used to dry the substrate and solves the problem of non-uniform film thickness during the drying process to some extent, it is very difficult to precisely control the pressure during the actual drying process and ensure that the state of the drying process is stable, so that the display quality of different areas may not be consistent after the actual drying process, which will deteriorate the display quality.

[0022] Another prior art provides a detection module to detect the thickness of the film layer, and analyzes the difference in film thickness at each point on the surface of the film layer based on the detected data of the thickness of the film layer, and then modifies the number of ink droplets printed accordingly. However, in this solution, the compensation for the number of ink droplets printed does not include the subsequent drying process, and the subsequent drying and baking processes also cause the film thickness to be non-uniform in the pixel groove, and when only compensating for the number of ink droplets printed, the distribution factor of the ink droplets is ignored, which causes the problem that the film thickness uniformity of the printed display image is not guaranteed.

[0023] The present application can be applied to a system as shown in FIG. 1. The system includes an ink drop observation device 10, an OLED inkjet device 20, a film thickness detector 30, a drying device 40, a substrate 50, and a processor 60. The OLED inkjet device 20 includes a plurality of inkjet heads 21. The ink drop observation device 10 may also include a CCD high-speed camera and a flash unit. The ink drop observation device 10 captures an image of the trajectory of the ink drop of the inkjet head, and analyzes and detects it. From the captured image, the trajectory of the ink drop discharged from the inkjet head is obtained, and data such as the speed of the ink drop, the volume of the ink drop, satellite ink drops, and tailing are measured to determine whether the ink is good or bad, and the voltage of the control board of the inkjet head, the control waveform of the inkjet head, and the mutual adaptation situation between the ink are adjusted to improve the printing accuracy.

[0024] The OLED inkjet device 20 is a type of device similar to inkjet printing, which prints OLED pixel points directly onto a glass or plastic bottom plate by a moving platform and an inkjet head according to an inkjet pattern set by a user. The OLED inkjet device 20 usually uses an inkjet head with multiple inkjet holes, with one or more inkjet heads having thousands of inkjet holes.

[0025] Drying unit 40 is a drying chamber and is used to dry the pattern having a display area, the display area being wetted with OLED material dissolved or suspended in a volatile carrier liquid.

[0026] The thickness detector 30 provides different light colors and illuminances to the parts to be detected by the lighting system of the device, and uses a high-resolution CCD camera to collect images of the parts to be detected, transmit them to a computer processing system, compare them with the grayscale of a standard image, perform discrimination analysis, and finally output the detection result. It is used to measure the uniformity of the thickness of the film formed in the OLED product. The thickness detector 30 is an existing device in the prior art, and outputs the corresponding thickness measurement result. The thickness detector 30 compares the position and size of the grayscale deviation of the image after each pixel is grayscale processed, and selects pixels that are different from the position and size of the grayscale image of other pixels, and compares it with the printing requirements to output the corresponding thickness detection parameters.

[0027] After the inkjet is completed, the OLED substrate can be transferred into a drying device 40 for baking. The film thickness detector 30 can detect the thickness of the ink droplets in each pixel groove on the OLED substrate and the baked film thickness, and then feed back to the processor 60. The processor 60 controls the inkjet head 21 to perform compensation inkjetting based on the received feedback, so that the final film thickness reaches the target film thickness.

[0028] In one embodiment, as shown in FIG. 2, the present application provides a method for compensating film thickness uniformity in OLED inkjet printing, the method including the following steps:

[0029] In step 110, obtain the target film thickness of the OLED, the mesh parameters of the pixel groove, and the parameters related to ink droplets of each inkjet head in the inkjet device, and calculate the inkjet volume and distribution of the ink droplets in each pixel groove according to the target film thickness, the mesh parameters, and the parameters related to ink droplets.

[0030] This application is applied to the processor shown in Figure 1. First, each pixel groove on the substrate is meshed. Specifically, as shown in Figure 3, each pixel groove is divided into a plurality of meshed regions, and each pixel groove has 20 regions. The size of each region is the minimum print region that the inkjet device can realize. After meshing, mesh parameters of each pixel groove are obtained.

[0031] The processor first obtains various pre-stored parameters, specifically including a target film thickness of the OLED, mesh parameters of the pixel groove, and parameters related to ink droplets of each inkjet head in the inkjet device, and the parameters related to ink droplets include a volume of ink droplets ejected by each inkjet hole in each inkjet head.

[0032] In one embodiment, obtaining the target film thickness of the OLED, mesh parameters of pixel grooves, and parameters related to ink droplets of each inkjet head in the inkjet device includes controlling each inkjet head in the inkjet device to eject ink droplets, obtaining a first image of the ink droplets, and determining the parameters related to ink droplets of each inkjet head based on the first image.

[0033] Specifically, different ink droplet materials may affect the volume of the ink droplets, and even the same holes may cause the volume of the ink droplets to change due to the aging of the device, etc. Therefore, in this embodiment, first, each inkjet head in the inkjet device is controlled to eject ink droplets, and an image of each ejected ink droplet is obtained and defined as a first image, and parameters related to the ink droplets of each inkjet head are identified based on the first image. For the specific process, please refer to the prior art.

[0034] After obtaining the target film thickness of the OLED, the mesh parameters of the pixel groove and the parameters related to the ink droplets of each inkjet head in the inkjet device, a weighting calculation is performed based on the target film thickness to obtain the volume and distribution of the ink droplets required for each mesh, that is, to obtain the inkjet volume and distribution of the ink droplets in each pixel groove.

[0035] In addition, each inkjet head in the inkjet device includes a plurality of inkjet holes, and each inkjet head can eject ink droplets of at least two different volumes through the corresponding plurality of inkjet holes; and calculating the inkjet volume and distribution status of the ink droplets in each pixel groove based on the target film thickness, mesh parameters, and parameters related to the ink droplets is Obtaining ink drop volumes and linear combinations ejected by each inkjet head into each pixel groove; Calculating the inkjet volume and distribution of the ink droplets in each pixel groove based on the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove, the target film thickness, mesh parameters, and ink droplet-related parameters.

[0036] Specifically, through the obtained pixel meshing, the ink drop volume of the minimum printable area of ​​each pixel groove after division is controlled by the driving waveform of the inkjet head and the switching of the inkjet holes, thereby realizing ink drops with fixed and selectable volume sizes for each minimum printable area, which means that the ink drop volume of a single pixel groove is a linear combination of the ink drop volume sizes of multiple minimum printable areas, as shown in Figure 4 for example, the ink drop volume of a single pixel groove is a linear combination of the ink drop volume sizes of multiple minimum printable areas. Figure 4 shows several combinations of printing ink drops, and in specific implementation, various ink drop combinations can be obtained by arranging and combining according to each inkjet hole in the inkjet head.

[0037] In addition, obtaining the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove is obtaining a difference between an ink drop volume in each pixel groove and a volume of each pixel groove at the target film thickness; and performing iterative calculations based on the volume differences to obtain ink drop volumes and linear combinations for each pixel well.

[0038] Specifically, the difference between the volume of the pixel groove and the volume of the pixel groove at the target film thickness is used as a cost function, and then a method for combining the size and distribution of the ink droplet volume in the pixel groove is obtained through sequential optimization calculation.

[0039] In step 120, ink is applied to each pixel groove based on the inkjet volume and distribution within each pixel groove.

[0040] In step 130, a baking process is performed on each pixel groove, and the film thickness of each mesh in each baked pixel groove is obtained.

[0041] Specifically, after obtaining the inkjet volume and distribution status of each pixel groove, the inkjet device is controlled to perform inkjet printing within each pixel groove, and after the inkjet printing is completed, the inkjet-printed substrate is transported to a drying device for drying. The printing and drying process may refer to the prior art and is not limited here.

[0042] 5, for example, because inkjet is performed on different meshes, the film thickness at different positions may be different after blending, and the position and shape of each ink drop before blending, as shown in M1 and M3, the size of the three ink drops in M1 is the same, and after the three ink drops are blended, as shown in M2, the liquid surface at each mesh position is basically flat, and the three ink drops in M3 are large in the middle and small on both sides, so that after blending, the middle is high and both sides are low. Therefore, in the present invention, after drying is completed, the thickness of the film in each mesh after drying is measured to obtain the film thickness of each mesh in each pixel groove.

[0043] In step 140, a compensation inkjet volume for each mesh in each pixel groove is determined based on the film thickness of each mesh in each pixel groove and the target film thickness, and inkjet is performed on each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness.

[0044] Based on the film thickness of each mesh obtained in step 130, the difference between the film thickness of each mesh in each pixel groove and the target film thickness is determined, a compensation inkjet volume for each mesh is determined, and inkjet is performed on each mesh in each pixel groove according to the compensation inkjet volume. After inkjet is completed, a bake process is performed again, and the film thickness of each baked mesh is obtained again. Based on the film thickness of each mesh obtained again, the difference between the target film thickness is determined, and if a difference exists, the compensation inkjet volume is determined again, and the compensation inkjet and bake process are performed again until the film thickness of each pixel groove reaches the target film thickness, and the film thickness is determined again.

[0045] According to the above-mentioned method for compensating for the thickness uniformity of OLED inkjet printing, by obtaining the target thickness of the OLED, the mesh parameters of the pixel groove, and the parameters related to the ink droplets of each inkjet head in the inkjet device, the inkjet volume and distribution of the ink droplets in each pixel groove are calculated based on the target thickness, the mesh parameters, and the parameters related to the ink droplets. Inkjet is performed for each pixel groove based on the inkjet volume and distribution in each pixel groove. A bake process is performed for each pixel groove, and the film thickness of each mesh in each baked pixel groove is obtained. Based on the film thickness of each mesh in each pixel groove and the target film thickness, a compensation inkjet volume of each mesh in each pixel groove is determined, and inkjet is performed for each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness. According to the above-mentioned method, the present invention meshes each pixel groove, and calculates the ink droplet volume and distribution of each mesh in each pixel groove, and after baking, the film thickness of each pixel groove is obtained, and based on the film thickness of each pixel groove and the target film thickness, a compensation inkjet volume of each mesh in each pixel groove is determined, and inkjet is performed again. In this way, the film thickness error caused by the bake process can be avoided. The use of an improved drying device in the prior art solves the problem of design complexity caused by non-uniform film thickness, reduces the design complexity, and ensures film thickness uniformity. In addition, this embodiment adds a drying process to the flow to solve the problem of non-uniform film thickness in pixel grooves caused by the non-consideration of processes such as drying and baking in the prior art printing compensation technology, and improves the accuracy of film thickness uniformity detection.

[0046] In one embodiment, as shown in FIG. 6, the step of calculating the inkjet volume and distribution of the ink droplets in each pixel groove according to the target film thickness, the mesh parameters, and the parameters related to the ink droplets includes: In step 111, acquiring an image of a substrate on which the pixel grooves are located, and classifying each pixel groove into a corresponding pixel groove type based on the image; In step 112, calculating the inkjet volume and distribution of the ink droplets in each pixel groove based on the target film thickness, the mesh parameters, the ink droplet related parameters and the type of each pixel groove.

[0047] Specifically, considering the influence of different pixel groove positions, in this embodiment, each pixel groove is classified into different types based on the position of each pixel groove. For example, referring to FIG. 7, based on the acquired image of the substrate, the position of each pixel groove on the substrate is identified, and each pixel groove is classified into a corresponding pixel groove type, the pixel groove type includes at least one of single edge pixel grooves (e.g., pixel grooves shown by A2 in FIG. 7) adjacent to one edge of the substrate, double edge pixel grooves (e.g., pixel grooves shown by A1 in FIG. 7) adjacent to two edges of the substrate, and internal pixel grooves (e.g., pixel grooves shown by A3 in FIG. 7) located inside the substrate, and in a specific embodiment, the pixel grooves can be classified into other types. After identifying the type of each pixel groove, the inkjet volume and distribution status of the ink droplets in each pixel groove are calculated based on the target film thickness, mesh parameters, parameters related to the ink droplets, and the type of each pixel.

[0048] In one embodiment, calculating an inkjet volume and distribution status of ink droplets in each pixel groove based on a linear combination of ink droplet volumes ejected by each inkjet head into each pixel groove, a target thickness of the OLED, mesh parameters, and ink droplet-related parameters, Obtaining an inkjet matrix of a plurality of pixel grooves that can be completed per unit step number of each inkjet head according to the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; and obtaining a minimum number of inkjet steps, and thus an inkjet volume and distribution of ink droplets in each pixel groove, based on the number of pixel grooves in the substrate and an inkjet matrix of multiple pixel grooves that can be completed per unit step number.

[0049] Specifically, each inkjet hole has two or more ink droplet volume sizes, and each inkjet hole has a slight difference in the volume ejected. In order to ensure the accuracy of the ink droplet volume and to improve the printing efficiency by using the minimum number of steps during printing, a matrix mathematics execution optimization method is used to generate printing landing point and waveform selection data according to the acquired ink droplet-related parameters, the inkjet volume and distribution of the ink droplets in each pixel groove acquired in step 110, and the coordinates of the pixel groove of the substrate as input.

[0050] In addition, during the printing process, each pixel groove cannot meet the printing requirements with only one movement of the inkjet head, and one inkjet head array prints multiple pixel grooves at the same time, which requires printing by successive step movements of the inkjet head, which leads to the problem of the minimum number of steps. Based on the inkjet volume and distribution status of the ink droplets in each pixel groove obtained in step 110, the ink droplet size distributions of multiple pixel grooves that can be maximally printed by one inkjet head array in one go are combined into one large ink droplet distribution matrix, and then, through an optimization method, the minimum number of steps of the inkjet head movement is taken as the target function using matrix calculation, and the waveform selection data corresponding to the final printing landing point and the size of the ink droplet volume can be identified.

[0051] In addition, the particle swarm optimization algorithm is selected as the optimization method, which is a branch of evolutionary computation and a random search algorithm that simulates biological activities in nature. In using this method, the inkjet holes in the entire array of the inkjet head are regarded as "particles", the corresponding search space is the inkjet volume and distribution situation of the ink droplets in each pixel groove obtained in step 110, and a global optimum value and a fitness function are set according to the minimum number of steps in the printing process of the entire substrate, and the optimum value is correspondingly updated once during the global search until the minimum number of printing steps that meets the termination condition is obtained, and after the number of printing steps is obtained, the unique solution of the corresponding ink droplet volume size and distribution scheme can be identified.

[0052] determining a compensation inkjet volume for each mesh in each pixel groove based on the film thickness of each mesh in each pixel groove and the target film thickness, and ink-jetting each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness; Obtaining the target film thickness and a film thickness supplement parameter for each mesh film thickness in each pixel groove that has been previously baked; obtaining an ink drop replenishment volume for each pixel groove based on the film thickness replenishment parameters and a preset weighting parameter; and sequentially optimizing the ink drop volume and distribution combination scheme for each pixel groove based on the ink drop refill volume for each pixel groove to obtain the ink drop volume and distribution combination scheme for each pixel groove.

[0053] Also, obtaining the ink droplet replenishment volume of each pixel groove based on the film thickness replenishment parameter and a preset weighting parameter, Identifying a type of each pixel groove and identifying a weighting parameter corresponding to each pixel groove film thickness fill parameter based on each pixel groove type.

[0054] TIFF2025503510000002.tif53170

[0055] TIFF2025503510000003.tif23167

[0056] In this way, the inkjet volume corresponding to each pixel groove in region A1 can be identified.

[0057] TIFF2025503510000004.tif57170

[0058] TIFF2025503510000005.tif47169

[0059] TIFF2025503510000006.tif40169

[0060] where J(w) is the cost function, m is the total number of pixel slots, w is the number of each mesh ink drop in the pixel slot, and y i is the ink drop refill volume in the pixel groove (V calculated as above) A1 , V A2 , V A3 ), w new are the parameters currently used, and w old are the parameters used in the previous step, η is the learning rate, and ▽ w J(w) is a gradient operator, which is obtained by an existing algorithm based on the cost function J(w), and X i represents the parameters related to the ink droplets of each inkjet head. i The product of and w represents the inkjet volume per unit mesh, and the combination of the inkjet volumes of each mesh in each pixel groove constitutes the inkjet volume and distribution status of each pixel groove. In the iteration process, iteration is performed with the aim of minimizing the cost function J(w), and finally X i The values ​​of and w were obtained, i.e., the inkjet head (or inkjet volume per inkjet) and the number of inkjet prints used for each mesh were obtained.

[0061] In one embodiment, a minimum number of inkjet steps is specified, i.e., the inkjet head to be used, i.e., the combination of the target inkjet heads is specified, and the minimum inkjet is the distance that the inkjet holes must move to move from the first printing point to the last printing point during the printing process. Then, each inkjet head is controlled according to the specified target inkjet head combination and the compensation inkjet volume to print on the target pixel groove, specifically, a print image of the target pixel groove is first generated according to the target inkjet head combination and the compensation inkjet volume, and the print image is a pre-printed image, and a corresponding image is obtained according to the size and position distribution of the ink drop volume that the target inkjet hole combination can eject. Then, each inkjet hole is controlled according to the print image of each pixel groove to print on each pixel groove.

[0062] As can be understood, although the steps in the flowcharts according to the above-mentioned embodiments are shown sequentially in the order indicated by the arrows, these steps do not necessarily have to be performed sequentially in the order indicated by the arrows. The execution of these steps is not limited to a strict order and may be performed in other orders unless expressly stated herein. In addition, at least some of the steps in the flowcharts according to the above-mentioned embodiments may include multiple steps or multiple stages, and these steps or stages do not necessarily have to be performed simultaneously but may be performed at different times, and the order of execution of these steps or stages does not necessarily have to be performed sequentially but may be performed alternately with other steps or at least some of the steps or stages of other steps.

[0063] Based on the same inventive concept, the embodiments of the present application further provide an OLED inkjet printing thickness uniformity compensation device for realizing the OLED inkjet printing thickness uniformity compensation method according to the above description. The technical solutions provided by the device to solve the problem are similar to the technical solutions described in the above method, so that the specific limitations of one or more OLED inkjet printing control device embodiments provided below may refer to the limitations of the OLED inkjet printing thickness uniformity compensation method described above, and will not be repeated here.

[0064] In one embodiment, as shown in FIG. 8, an apparatus for compensating thickness uniformity of OLED inkjet printing is provided, which includes the following modules:

[0065] The acquisition module 810 is used to acquire the target thickness of the OLED, the mesh parameters of the pixel groove and the parameters related to the ink droplets of each inkjet head in the inkjet device, and calculate the inkjet volume and distribution status of the ink droplets in each pixel groove according to the target thickness of the OLED, the mesh parameters and the parameters related to the ink droplets.

[0066] The inkjet module 820 is used to inkjet each pixel groove according to the inkjet volume and distribution in each pixel groove.

[0067] The film thickness acquisition module 830 is used to perform a baking process on each pixel groove and acquire the film thickness of each mesh in each baked pixel groove.

[0068] The refill module 840 is used to determine a compensation inkjet volume for each mesh in each pixel groove based on the film thickness of each mesh in each pixel groove, and inkjet each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches a target film thickness.

[0069] In one embodiment, the acquisition module 810 includes: The method is used to control each inkjet head in an inkjet device to eject ink droplets, obtain a first image of the ink droplets, and identify parameters related to the ink droplets of each inkjet head based on the first image.

[0070] In one embodiment, the acquisition module 810 includes: acquiring an image of a substrate in which the pixel grooves are located, and classifying each pixel groove into a corresponding pixel groove type based on the image; Based on the target film thickness, mesh parameters, ink drop related parameters and each pixel groove type, it is used to calculate the ink jet volume and distribution of the ink drop within each pixel groove.

[0071] In one embodiment, the types of pixel grooves include at least one of a single-edge pixel groove adjacent to one edge of the substrate, a double-edge pixel groove adjacent to two edges of the substrate, and an internal pixel groove located inside the substrate.

[0072] In one embodiment, the replenishment module 840 includes: Acquire the target film thickness and a film thickness supplement parameter for each mesh film thickness in each pixel groove that has been previously baked; obtaining an ink drop replenishment volume for each pixel groove based on the film thickness replenishment parameters and preset weighting parameters; Based on the ink drop refill volume of each pixel groove, iterative optimization is performed to obtain a compensation ink drop volume and distribution combination scheme for each pixel groove.

[0073] In one embodiment, the replenishment module 840 includes: A type for each pixel groove is identified and used to identify a weighting parameter corresponding to each pixel groove film thickness fill parameter based on each pixel groove type. In one embodiment, each inkjet head in the inkjet device includes a plurality of inkjet holes, and each inkjet head can eject ink droplets of at least two different volumes through the corresponding plurality of inkjet holes. The acquisition module 810: Acquire the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; Based on the ink drop volume and linear combination of the ink drop volume ejected by each inkjet head into each pixel groove, the target film thickness, the mesh parameters and the ink drop-related parameters, it is used to calculate the ink drop ink volume and distribution status in each pixel groove.

[0074] In one embodiment, the acquisition module 810 includes: obtaining a difference between the ink droplet volume in each pixel groove and the volume of each pixel groove at the target film thickness; Based on the volume differences, iterative calculations are then used to obtain the ink drop volume and linear combinations for each pixel channel.

[0075] In one embodiment, the acquisition module 810 includes: Obtain an inkjet matrix of a plurality of pixel grooves that can be completed per unit step number of each inkjet head according to the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; Based on the number of pixel grooves in the substrate and the inkjet matrix of multiple pixel grooves that can be completed per unit step, this is used to obtain the minimum number of inkjet steps and therefore the inkjet volume and distribution of ink droplets in each pixel groove.

[0076] In one embodiment, the size of each mesh within each pixel groove is the size of the smallest print area that the inkjet device can achieve.

[0077] Each module in the above-mentioned OLED inkjet printing thickness uniformity compensation device can be realized in whole or in part by software, hardware, and a combination thereof. Each module can be embedded or independent in the processor of a computer device in the form of hardware, or can be stored in the memory of a computer device in the form of software, so that the processor can call and execute the operations corresponding to each module.

[0078] In one embodiment, a computer device is provided, the computer device being a server, and its internal block diagram is shown in FIG. 9. The computer device includes a processor, a memory, and a network interface connected by a system bus. The processor of the computer device is used to provide calculation and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. An operating system, a computer program, and a database are stored in the non-volatile storage medium. The internal memory provides an environment for the execution of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data such as a target film thickness, mesh parameters of pixel grooves, and parameters related to ink droplets of each inkjet head in an inkjet device. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, steps of a method for compensating for film thickness uniformity in OLED inkjet printing are performed.

[0079] Those skilled in the art will appreciate that the configuration shown in FIG. 9 is a block diagram of only a portion of the configuration relevant to the solution of the present application and is not intended to limit the computing devices to which the solution of the present application may be applied, and that a particular computing device may include more or fewer components than those shown in the figure, may combine some components, or have a different arrangement of components.

[0080] In one embodiment, a computing device is provided, the computing device including a memory and a processor, the memory storing a computer program, the processor performing the following steps when executing the computer program:

[0081] obtain a target thickness of the OLED, a mesh parameter of a pixel groove, and a parameter related to an ink droplet of each inkjet head in an inkjet device; and calculate an inkjet volume and a distribution state of the ink droplet in each pixel groove based on the target thickness, the mesh parameter, and the parameter related to the ink droplet; Ink-jetting is performed on each pixel groove based on the ink-jet volume and distribution status in each pixel groove; A baking process is performed on each pixel groove, and the film thickness of each mesh in each baked pixel groove is obtained. A compensation inkjet volume for each mesh in each pixel groove is specified based on the film thickness of each mesh in each pixel groove and the target film thickness, and inkjet is performed on each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness.

[0082] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0083] Each inkjet head in an inkjet device is controlled to eject ink droplets, a first image of the ink droplets is obtained, and parameters relating to the ink droplets of each inkjet head are identified based on the first image.

[0084] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0085] acquiring an image of a substrate in which the pixel grooves are located, and classifying each pixel groove into a corresponding pixel groove type based on the image; Based on the target film thickness, mesh parameters, ink drop related parameters and each pixel groove type, the ink jet volume and distribution of the ink drop within each pixel groove is calculated.

[0086] In one embodiment, the types of pixel grooves include at least one of a single-edge pixel groove adjacent to one edge of the substrate, a double-edge pixel groove adjacent to two edges of the substrate, and an internal pixel groove located inside the substrate.

[0087] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0088] Acquire the target film thickness and a film thickness supplement parameter for each mesh film thickness in each pixel groove that has been previously baked; obtaining an ink drop replenishment volume for each pixel groove based on the film thickness replenishment parameters and preset weighting parameters; Based on the ink drop refill volume of each pixel groove, iterative optimization is performed to obtain a compensation ink drop volume and distribution combination scheme for each pixel groove.

[0089] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0090] A type of each pixel groove is identified, and a weighting parameter corresponding to each pixel groove film thickness fill parameter is identified based on each pixel groove type.

[0091] In one embodiment, each inkjet head in the inkjet device includes a plurality of inkjet holes, and each inkjet head can eject ink droplets of at least two different volumes through the corresponding plurality of inkjet holes.

[0092] When the processor executes the computer program, it further performs the following steps.

[0093] Acquire the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; The inkjet volume and distribution of the ink droplets in each pixel groove are calculated based on the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove, the target film thickness, mesh parameters, and ink droplet-related parameters.

[0094] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0095] obtaining a difference between the ink droplet volume in each pixel groove and the volume of each pixel groove at the target film thickness; An iterative calculation is performed based on the volume differences to obtain the ink drop volume and linear combination for each pixel well.

[0096] In one embodiment, when the processor executes the computer program, it further performs the following steps:

[0097] Obtain an inkjet matrix of a plurality of pixel grooves that can be completed per unit step number of each inkjet head according to the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; Based on the number of pixel grooves in the substrate and the inkjet matrix of multiple pixel grooves that can be completed per unit step number, the minimum inkjet step number and thus the inkjet volume and distribution of ink drops in each pixel groove are obtained.

[0098] In one embodiment, a computer readable storage medium is provided having a computer program stored thereon, the computer program, when executed by a processor, performing the steps of the method for compensating for film thickness uniformity in OLED inkjet printing as described in any of the embodiments above.

[0099] Those skilled in the art will understand that implementing all or part of the processes of the methods of the above-mentioned embodiments can be completed by instructing relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium, and when the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. In addition, any reference to a memory, database, or other medium used in each embodiment provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. For purposes of explanation and not limitation, the RAM may be in various forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The database according to the embodiments provided herein may include at least one of a relational database and a non-relational database. The non-relational database may include, but is not limited to, a distributed database based on a blockchain. The processor according to the embodiments provided herein may be, but is not limited to, a general-purpose processor, a central processor, a graphics processor, a digital signal processor, programmable logic, data processing logic based on quantum computing, etc.

[0100] Each of the technical features in the above embodiments can be combined in any combination, and for the sake of brevity, not all possible combinations of each of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, any of them should be considered within the scope described in this specification.

[0101] The above examples only show some embodiments of the present application, and the description is specific and detailed, but should not be understood as limiting the scope of the present application. However, a person skilled in the art can make several modifications and improvements without departing from the concept of the present application, all of which are within the scope of protection of the present application. Therefore, the scope of protection of the present application should be determined based on the scope of the attached claims.

Claims

1. 1. A method for compensating for film thickness uniformity in OLED inkjet printing, comprising: The method comprises: Obtaining a target film thickness of the OLED, a mesh parameter of a pixel groove, and a parameter related to an ink droplet of each inkjet head in an inkjet device, and calculating an inkjet volume and a distribution state of the ink droplet in each pixel groove based on the target film thickness, the mesh parameter, and the parameter related to the ink droplet; performing ink jetting for each pixel groove based on the ink jet volume and distribution status within each pixel groove; performing a baking process on each pixel groove and acquiring a film thickness of each mesh in each baked pixel groove; determining a compensation inkjet volume for each mesh in each pixel groove based on a film thickness of each mesh in each pixel groove and the target film thickness, and inkjetting each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness.

2. Obtaining the target film thickness of the OLED, the mesh parameters of the pixel groove, and the parameters related to the ink droplets of the inkjet head in the inkjet device, 2. The method of claim 1, comprising controlling each inkjet head in an inkjet device to eject ink droplets, obtaining a first image of the ink droplets, and identifying parameters related to the ink droplets of each inkjet head based on the first image.

3. calculating an inkjet volume and distribution of ink droplets in each pixel groove based on the target film thickness, mesh parameters, and ink droplet related parameters; acquiring an image of a substrate in which the pixel grooves are located, and classifying each pixel groove into a corresponding pixel groove type based on the image; and calculating an inkjet volume and distribution of ink drops in each pixel groove based on the target film thickness, mesh parameters, ink drop related parameters and each pixel groove type.

4. 4. The method of claim 3, wherein the pixel groove types include at least one of a single-edge pixel groove adjacent one edge of a substrate, a double-edge pixel groove adjacent two edges of a substrate, and an internal pixel groove located within a substrate.

5. determining a compensation inkjet volume for each mesh in each pixel groove based on the film thickness of each mesh in each pixel groove and the target film thickness, and ink-jetting each mesh in each pixel groove according to the compensation inkjet volume until the film thickness of each pixel groove reaches the target film thickness; Obtaining the target film thickness and a film thickness supplement parameter for each mesh film thickness in each pixel groove that has been previously baked; obtaining an ink drop replenishment volume for each pixel groove based on the film thickness replenishment parameters and a preset weighting parameter; 4. The method of claim 3, further comprising: performing iterative optimization based on the ink drop refill volume of each pixel groove to obtain a compensation ink drop volume and distribution combination scheme for each pixel groove.

6. obtaining an ink drop replenishment volume for each pixel groove based on the film thickness replenishment parameters and a preset weighting parameter; 6. The method of claim 5, further comprising identifying a type of each pixel groove and identifying a weighting parameter corresponding to each pixel groove film thickness fill parameter based on each pixel groove type.

7. Each inkjet head in the inkjet device includes a plurality of inkjet holes, and each inkjet head can eject ink droplets of at least two different volumes through the corresponding plurality of inkjet holes; and calculating an inkjet volume and a distribution state of the ink droplets in each pixel groove based on the target film thickness, mesh parameters, and parameters related to the ink droplets; Obtaining ink drop volumes and linear combinations ejected by each inkjet head into each pixel groove; and calculating an inkjet volume and distribution of ink droplets in each pixel groove based on a linear combination of ink droplet volumes ejected by each inkjet head into each pixel groove, the target film thickness, mesh parameters, and ink droplet-related parameters.

8. Obtaining the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove includes: obtaining a difference between an ink drop volume in each pixel groove and a volume of each pixel groove at the target film thickness; and performing iterative calculations based on the volume differences to obtain ink drop volumes and linear combinations for each pixel well.

9. Calculating an inkjet volume and a distribution state of the ink droplet in each pixel groove based on the ink droplet volume and linear combination of the ink droplets ejected by each inkjet head into each pixel groove, the target film thickness of the OLED, mesh parameters, and parameters related to the ink droplets; Obtaining an inkjet matrix of a plurality of pixel grooves that can be completed per unit step number of each inkjet head according to the ink droplet volume and linear combination ejected by each inkjet head into each pixel groove; 8. The method of claim 7, further comprising: obtaining a minimum number of inkjet steps, and thus an inkjet volume and distribution of ink droplets in each pixel groove, based on the number of pixel grooves in the substrate and an inkjet matrix of multiple pixel grooves that can be completed per unit step.

10. 10. The method according to claim 1, wherein the size of each mesh in each pixel groove is the size of the smallest printing area that can be realized by an inkjet device.

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