Diffusion domain simulation method and device for inhibiting coffee ring effect in OLED ink-jet printing

Abstract

The embodiment of the invention provides a diffusion domain simulation method and device for inhibiting a coffee ring effect in OLED ink-jet printing, and belongs to the technical field of ink-jet printing. The method comprises the following steps: acquiring a first ink-jet printing scheme to be evaluated, wherein the first ink-jet printing scheme comprises a plurality of printing parameters; ink-jet printing simulation is conducted according to the multiple printing parameters, the liquid drop state of the first ink-jet printing scheme is obtained, and the liquid drop state is the final state of liquid drops on a substrate; determining the surface flatness of the liquid drop according to the liquid drop state; and determining an evaluation result of the first ink-jet printing scheme according to the surface flatness of the liquid drops. According to the embodiment of the invention, the film forming quality of ink-jet printing under different experimental parameters can be quickly evaluated through the simulation model, so that the ink-jet printing effect is optimized by adjusting a plurality of key printing parameters in the ink-jet printing scheme, and the uniformity of a film layer in the ink-jet printing process is improved.

Description

Technical Field

[0001] The present application relates to the technical field of inkjet printing, and particularly to a diffusion domain simulation method and device for suppressing the coffee ring effect in OLED inkjet printing. Background Art

[0002] With the wide application of inkjet printing technology in the manufacturing of organic light-emitting diode (OLED) display devices, film formation uniformity has become a key factor affecting device performance. During the inkjet printing process, film formation uniformity is often easily affected by the coffee ring effect, which is caused by different evaporation rates at the edges and the central region when the ink droplets evaporate, causing the solute to migrate from the center of the substrate to the edges, resulting in uneven film formation layers, and thus seriously affecting the brightness, efficiency, and service life of OLED devices.

[0003] Traditional solutions usually rely on real experiments to adjust relevant parameters in inkjet printing, such as changing external environmental conditions (such as temperature, humidity), geometric structures, or adding surfactants, to optimize the film formation effect of inkjet printing, and thus solve the problem of poor film formation uniformity caused by the coffee ring effect in inkjet printing. However, in real experiments, in order to achieve a better film formation effect, it is necessary to adjust the relevant parameters of inkjet printing multiple times, which requires a lot of time cost and results in low efficiency in solving problems. Summary of the Invention

[0004] The main purpose of the embodiments of the present application is to propose a diffusion domain simulation method and device for suppressing the coffee ring effect in OLED inkjet printing, aiming to provide an evaluation method for inkjet printing solutions, and quickly evaluating the film formation quality of inkjet printing under different experimental parameters through a simulation model.

[0005] To achieve the above object, a first aspect of the embodiments of the present application proposes a diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing, the method comprising:

[0006] Obtaining a first inkjet printing solution to be evaluated, the first inkjet printing solution including a plurality of printing parameters;

[0007] Performing inkjet printing simulation according to the plurality of printing parameters to obtain the droplet state of the first inkjet printing solution, the droplet state being the final state of the droplet on the substrate;

[0008] Determining the surface flatness of the droplet according to the droplet state;

[0009] Determining the evaluation result of the first inkjet printing solution according to the surface flatness of the droplet.

[0010] In some embodiments, at least two of the multiple printing parameters include the substrate shape, the shape of the inkjet printing droplet, the physical properties of the droplet, the initial concentration of the active agent, the diffusion coefficient of the active agent, the substrate interface characteristics, and the evaporation parameters;

[0011] Performing inkjet printing simulation according to the multiple printing parameters to obtain the droplet state of the first inkjet printing scheme, including:

[0012] Constructing an inkjet printing model based on the multiple printing parameters, where the inkjet printing model is used to simulate the droplet formation process and the spreading process of the droplet on the substrate in inkjet printing;

[0013] Performing inkjet printing simulation on the multiple printing parameters through the inkjet printing model to obtain the droplet state of the first inkjet printing scheme.

[0014] In some embodiments, constructing the inkjet printing model based on the multiple printing parameters includes:

[0015] Simulating the substrate shape and the shape of the inkjet printing droplet through a phase field function, and using the phase field method to describe the spreading process of the droplet on the substrate;

[0016] Simulating the evaporation process on the surface of the droplet according to the evaporation parameters;

[0017] Simulating the dissolution rate of the active agent in the droplet and the concentration distribution of the active agent on the surface of the droplet according to the surface thickness of the droplet and the diffusion coefficient of the active agent;

[0018] Simulating the mass conservation and momentum balance of the droplet during the printing process according to the density, viscosity, and surface tension of the droplet in the physical properties of the droplet;

[0019] Simulating the roughness of the substrate and the movement process of the contact line between the droplet and the substrate in the substrate interface characteristics according to the slip length;

[0020] Adopting a diffusion domain method, simulating the substrate structure through an interface function, and expanding the calculation region to a regular geometric region to obtain the inkjet printing model.

[0021] In some embodiments, determining the surface flatness of the droplet according to the droplet state includes:

[0022] Using the contour line of the phase field function to represent the droplet state, where the position where the contour line of the phase field function is 0 represents the surface of the droplet;

[0023] Calculate a target fitting line based on the position points on the surface of the droplet, where the sum of the perpendicular distances from the target fitting line to the position points on the surface of each droplet is minimized;

[0024] Determine the surface flatness of the droplet according to the deviation between the surface of the droplet and the target fitting line.

[0025] In some embodiments, the determining the surface flatness of the droplet according to the deviation between the surface of the droplet and the target fitting line includes:

[0026] Obtain the distances from each position point on the surface of the droplet to the target fitting line respectively;

[0027] Perform a sum-of-squares operation on the obtained distances to obtain a target sum of squares;

[0028] Take the square root of the target sum of squares as the error degree;

[0029] Perform flatness evaluation according to the error degree to obtain the surface flatness of the droplet.

[0030] In some embodiments, after determining the evaluation result of the first inkjet printing scheme, the method further includes:

[0031] Judge whether the score in the evaluation result of the first inkjet printing scheme exceeds a preset threshold;

[0032] If the score in the evaluation result of the first inkjet printing scheme exceeds the preset threshold, output the evaluation result of the first inkjet printing scheme;

[0033] If the score in the evaluation result of the first inkjet printing scheme does not exceed the preset threshold, determine the printing parameters to be optimized in the first inkjet printing scheme and the optimization interval corresponding to each printing parameter to be optimized, and output the evaluation result of the first inkjet printing scheme, the printing parameters to be optimized, and the optimization interval corresponding to each printing parameter to be optimized.

[0034] In some embodiments, after the step of if the score in the evaluation result of the first inkjet printing scheme does not exceed the preset threshold, determine the printing parameters to be optimized in the first inkjet printing scheme and the optimization interval corresponding to each printing parameter to be optimized, and output the evaluation result of the first inkjet printing scheme, the printing parameters to be optimized, and the optimization interval corresponding to each printing parameter to be optimized, the method further includes:

[0035] Take the first inkjet printing solution as the current inkjet printing solution, take the printing parameters to be optimized in the first inkjet printing solution as the target parameters, and take the optimization interval corresponding to the printing parameters to be optimized as the target interval;

[0036] Regenerate a plurality of temporary inkjet printing solutions according to the target parameters of the current inkjet printing solution and the target interval corresponding to the target parameters;

[0037] Perform inkjet printing simulation on each of the temporary inkjet printing solutions to obtain an evaluation result corresponding to each of the temporary inkjet printing solutions;

[0038] Take the temporary inkjet printing solution corresponding to the evaluation result with the highest score among the evaluation results corresponding to the plurality of temporary inkjet printing solutions as the target inkjet printing solution;

[0039] If the score in the evaluation result of the target inkjet printing solution exceeds a preset threshold, output the evaluation result of the target inkjet printing solution;

[0040] If the score in the evaluation result of the target inkjet printing solution does not exceed the preset threshold, determine the printing parameters to be optimized in the target inkjet printing solution and the optimization interval corresponding to each of the printing parameters to be optimized;

[0041] Take the target inkjet printing solution as the current inkjet printing solution, take the printing parameters to be optimized in the target inkjet printing solution as the target parameters, and take the optimization interval corresponding to the printing parameters to be optimized as the target interval, and execute the step of regenerating a plurality of temporary inkjet printing solutions according to the target parameters of the current inkjet printing solution and the target interval corresponding to the target parameters;

[0042] If the score in the evaluation result of the target inkjet printing solution exceeds the preset threshold, output the evaluation result of the target inkjet printing solution.

[0043] To achieve the above object, a second aspect of the embodiments of the present application proposes a diffusion domain simulation device for suppressing the coffee ring effect in OLED inkjet printing, and the device includes:

[0044] An acquisition module, which acquires a first inkjet printing solution to be evaluated, and the first inkjet printing solution includes a plurality of printing parameters;

[0045] A simulation module, which performs inkjet printing simulation according to the plurality of printing parameters to obtain the droplet state of the first inkjet printing solution, and the droplet state is the final state of the droplet on the substrate;

[0046] A calculation module, which determines the surface flatness of the droplet according to the droplet state;

[0047] An evaluation module determines an evaluation result of the first inkjet printing scheme according to the surface flatness of the droplet.

[0048] To achieve the above object, a third aspect of the embodiments of the present application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the method described in the first aspect above is implemented.

[0049] To achieve the above object, a fourth aspect of the embodiments of the present application provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the method described in the first aspect above is implemented.

[0050] The diffusion domain simulation method and device for suppressing the coffee ring effect in OLED inkjet printing proposed in the present application perform inkjet printing simulation on multiple key printing parameters in the inkjet printing scheme input by the user, and obtain the final state of the droplets on the substrate in the inkjet printing scheme according to the simulation results; determine the surface flatness of the droplets according to the final state of the droplets; determine the evaluation result of the inkjet printing scheme according to the surface flatness. The higher the surface flatness, the better the inkjet printing scheme. The present application uses numerical simulation technology to quickly evaluate the film-forming effect of the inkjet printing scheme, and then optimizes the inkjet printing effect by adjusting multiple key printing parameters in the inkjet printing scheme, improving the uniformity of the film layer during the inkjet printing process. Description of the Drawings

[0051] Figure 1 is a schematic flow chart of the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiments of the present application;

[0052] Figure 2 is a numerical simulation schematic diagram of the spreading of inkjet printing droplets in the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiments of the present application;

[0053] Figure 3a is a schematic diagram of the substrate shape being an inclined plane structure provided by the embodiments of the present application;

[0054] Figure 3b is a schematic diagram of the substrate shape being a square structure provided by the embodiments of the present application;

[0055] Figure 3c is a schematic diagram of the substrate shape being a rectangular structure provided by the embodiments of the present application;

[0056] Figure 3d is a schematic diagram of the substrate shape being a cylindrical structure provided by the embodiments of the present application;

[0057] Figure 4 It is a schematic diagram of the coating changing hydrophilicity and hydrophobicity in the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application;

[0058] Figure 5 It is a schematic diagram of the inkjet printing process in the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application;

[0059] Figure 6 It is a schematic diagram of extending the calculation region to a regular region by using the diffusion region method in the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application;

[0060] Figure 7 It is a technical roadmap of the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application;

[0061] Figure 8 It is a schematic structural diagram of the diffusion domain simulation device for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application;

[0062] Figure 9 It is a schematic hardware structure diagram of the electronic device provided by an embodiment of the present application. Detailed implementation manners

[0063] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0064] It should be noted that although functional module division is performed in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order from the module division in the device or the flowchart in the flowchart. Terms such as "first" and "second" in the specification, claims and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0066] First, several nouns involved in the present application are analyzed:

[0067] Coffee Ring Effect: It refers to the phenomenon that when a drop of coffee or tea drips onto a tabletop, its particulate matter will leave a stained blot on the tabletop, and the color of the blot is uneven, with the edge part being darker than the middle, forming a ring-shaped spot. The formation of the coffee ring effect is mainly due to the uneven deposition during liquid evaporation. When a liquid droplet lands on a solid surface, the evaporation rate at the edge of the droplet is faster than that at the center, causing the solute particles in the center of the droplet to be carried to the edge and eventually forming a ring-shaped structure after drying. Specifically, during the evaporation process of the droplet, the water molecules at the edge evaporate faster, causing the solute particles in the center to be pushed towards the edge and gradually accumulate to form a ring-shaped stain. In inkjet printing technology, the ring-shaped structure formed after the droplet dries will affect the printing quality, so it is necessary to avoid the coffee ring effect to ensure the printing effect.

[0068] Phase Field Method: It is a mathematical modeling technique that is widely used in the fields of materials science and engineering to simulate and study the evolution process of multiphase systems. This technique can be used to describe interface dynamics problems, such as solidification, crystal growth, crack propagation, droplet formation, etc. The core idea of the phase field model is to introduce a continuous phase field variable to represent the transition region between different phases. At the interface between two phases, the phase field variable smoothly transitions from one value to another within a certain width, which is called the interface thickness. Although the interface may be very thin in the actual physical system, a finite thickness is artificially set in the phase field model for numerical stability. For inkjet printing, the phase field method can be used to simulate the interface behavior between the ink droplet and the air or the substrate. By solving the phase field equation and combining with the hydrodynamic equation (such as the Navier-Stokes equation), the shape evolution, fusion, splitting, spreading, etc. of the droplet can be predicted, and the effects of surface tension, viscosity, temperature, etc. on these behaviors can be considered.

[0069] Diffuse Domain Method (DDM): It is a numerical simulation technique based on the phase field method, mainly used to deal with interface evolution problems. The diffuse domain method simplifies the calculation process and improves the calculation efficiency by introducing a smooth function to describe the interface boundary and transforming the complex interface problem into a problem of solving partial differential equations in a regular region.

[0070] Navier slip boundary condition: It refers to the situation that when a fluid contacts a solid wall, the velocity distribution of the fluid at the wall is no longer zero, but there is a certain slip velocity. The traditional no-slip boundary condition assumes that the velocity of the fluid at the solid wall is zero, that is, there is no relative motion between the fluid and the solid wall. However, at the micro or nano scale, or when the solid surface has special textures, coatings or chemical properties, fluid molecules can slip to a certain extent on the solid surface. The Navier slip boundary condition assumes that there is a slip length between the velocity of the fluid on the solid surface and the velocity of the solid surface, and the slip length represents the degree of relative motion between the fluid and the solid surface. The magnitude of the slip length depends on the physical properties of the fluid and the solid surface, such as fluid viscosity, solid surface roughness and surface free energy, etc.

[0071] With the wide application of inkjet printing technology in the manufacture of OLED display devices, film formation uniformity has become a key factor affecting device performance. The common coffee ring effect in the inkjet printing process will cause the solute to migrate from the center of the substrate to the edge, ultimately resulting in non-uniform film formation, which will seriously affect the brightness, efficiency and service life of OLED devices.

[0072] Traditional solutions usually rely on changing external environmental conditions (such as temperature, humidity), geometric structures or adding active agents to control the fluidity of the solution. However, these methods are difficult to control precisely during the production process, have high requirements for solution stability, and have low structural design efficiency and long experimental cycles.

[0073] Based on this, the embodiments of the present application provide a diffusion domain simulation method, device, electronic device and storage medium for suppressing the coffee ring effect in OLED inkjet printing, aiming to quickly evaluate the film formation effect of inkjet printing under different experimental parameters through a simulation model, and then optimize the inkjet printing effect by adjusting multiple key printing parameters in the inkjet printing scheme, and improve the uniformity of the film layer during the inkjet printing process.

[0074] The diffusion domain simulation method, device, electronic device and storage medium for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiments of the present application are specifically described through the following embodiments. First, the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing in the embodiments of the present application is described.

[0075] The diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiments of the present application relates to the technical field of inkjet printing. The diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiments of the present application can be applied to a terminal, or to a server side, or can also be software running on a terminal or a server side. In some embodiments, the terminal can be a smart phone, a tablet computer, a notebook computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or can be configured as a server cluster or a distributed system composed of multiple physical servers, or can also be configured as a cloud server providing basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application for implementing the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing, etc., but is not limited to the above forms.

[0076] The present application can be used in many general or special computer system environments or configurations. For example: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronic devices, network PCs, minicomputers, mainframe computers, distributed computing environments including any of the above systems or devices, and so on. The present application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The present application can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0077] It should be noted that in each specific embodiment of the present application, when it comes to relevant processing that needs to be carried out according to data related to the user's identity or characteristics, such as user information, user behavior data, user historical data, and user location information, the user's permission or consent will be obtained first. Moreover, the collection, use, and processing of these data will comply with relevant laws, regulations, and standards. In addition, when the embodiments of the present application need to obtain the user's sensitive personal information, the user's separate permission or separate consent will be obtained through methods such as pop-up windows or redirecting to a confirmation page. After clearly obtaining the user's separate permission or separate consent, the necessary user-related data for the normal operation of the embodiments of the present application will be obtained.

[0078] Figure 1It is an alternative flowchart of the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by an embodiment of the present application. Figure 1 The method in

[0079] Step S100, obtain a first inkjet printing scheme to be evaluated, where the first inkjet printing scheme includes multiple printing parameters.

[0080] In this embodiment, first, obtain the inkjet printing scheme to be evaluated input by the user, and obtain multiple key printing parameters from the inkjet printing scheme to be evaluated. The first inkjet printing scheme is the inkjet printing scheme to be evaluated input by the user. The printing parameters include but are not limited to: substrate shape, shape of the inkjet printing droplet, physical properties of the droplet, initial concentration of the active agent, diffusion coefficient of the active agent, substrate interface characteristics, and evaporation parameters; among them, the substrate shape can be obtained based on image extraction or an analytical expression of the substrate shape; the shape of the inkjet printing droplet can be obtained by image extraction or an analytical expression of the droplet shape; the physical properties of the droplet can include: mass density of the droplet, dynamic viscosity of the droplet, and surface intermolecular tension of the droplet, etc.; the initial concentration of the active agent can be calculated according to the initial dosage of the active agent added in the experiment; the diffusion coefficient of the active agent can be obtained according to the dissolution (diffusion) rate of the corresponding active agent type in the liquid; the substrate interface characteristics can include: roughness, coating parameters, and microstructures, etc.; the roughness can be obtained according to the average roughness or fluctuation characteristic parameters of the interface, the coating parameters are obtained according to the thickness or material properties of the substrate coating, and the microstructures can be obtained according to the microscopic morphological characteristics of the substrate surface; the evaporation parameters can be obtained according to the evaporation rate corresponding to the humidity of the environment where the droplet is located.

[0081] In an implementation manner of this embodiment, the multiple printing parameters include at least two of the substrate shape, shape of the inkjet printing droplet, physical properties of the droplet, initial concentration of the active agent, diffusion coefficient of the active agent, substrate interface characteristics, and evaporation parameters.

[0082] This embodiment can accurately numerically simulate the droplet formation process in inkjet printing by inputting the inkjet printing scheme or multiple printing parameters in the inkjet printing scheme, such as the physical properties of the droplet, the initial concentration of the active agent, substrate interface characteristics, evaporation parameters, etc., so as to effectively obtain the inkjet printing scheme to be evaluated.

[0083] Step S200, perform inkjet printing simulation according to the multiple printing parameters to obtain the droplet state of the first inkjet printing scheme, where the droplet state is the final state of the droplet on the substrate.

[0084] In this embodiment, variables such as droplet, surfactant, substrate, and environmental parameters are set according to printing parameters. Specifically, the relevant variables of the droplet include but are not limited to: the initial shape, position, and physical properties (density, viscosity, surface tension, etc.) of the droplet; the relevant variables of the surfactant include but are not limited to: the initial concentration distribution and kinetic parameters (dissolution rate, adsorption characteristics, etc.) of the surfactant; the relevant variables of the substrate include but are not limited to: the interfacial characteristics of the substrate (roughness, coating parameters, microstructure, etc.); the relevant variables of the environmental parameters include but are not limited to: humidity, temperature, evaporation rate, etc.

[0085] Then, the phase field method is used to describe the droplet surface. Combining the kinetic processes of the surfactant on the droplet surface and boundaries, the Navier slip boundary condition is adopted to simulate the contact line movement and contact angle change, realizing the accurate simulation of droplet diffusion and interface evolution. And the diffusion domain method is used to embed the model into a regular region to improve the calculation efficiency.

[0086] In the diffusion domain simulation method, solving the equations of droplet motion, surfactant diffusion, and interface evolution is a key step. Since the droplet motion equation (Navier-Stokes equation) is nonlinear, appropriate numerical methods need to be used for solution. In this embodiment, a pressure-stabilized splitting method and a staggered grid finite difference method are used to solve the equations of droplet motion, surfactant diffusion, and interface evolution; and the CPU parallel multi-grid algorithm is adopted to decompose the computational region into multiple sub-regions and perform parallel calculations on different CPU cores, thereby accelerating the iterative process and improving the calculation efficiency. Solving the Navier-Stokes equation with the pressure-stabilized splitting method can effectively handle complex nonlinear problems in fluid dynamics; in terms of spatial discretization, a regular and efficient staggered grid finite difference method is adopted, which can improve the calculation efficiency while ensuring the calculation accuracy; combined with the self-developed CPU parallel multi-grid algorithm, it can quickly and effectively solve the equations of the entire droplet spreading process and perform efficient parallel calculations at multiple time steps. The calculation time of the entire simulation process usually remains at the hour level, and at the same time, this algorithm can run flexibly on different hardware platforms, ensuring the high efficiency and portability of the model, and being applicable to the simulation of large-scale and complex structures. Figure 2 Shows the numerical simulation of the entire inkjet printing droplet spreading under a set of experimental data.

[0087] Specifically, first, the Navier-Stokes equations are decomposed into a pressure Poisson equation and momentum equations. Second, a pressure-stabilized splitting method is adopted to decompose the Navier-Stokes equations into a pressure Poisson equation and momentum equations, which are solved separately; the pressure Poisson equation is solved first to obtain the pressure field, and then the velocity field is solved using the pressure field and the momentum equations. Then, a staggered grid finite difference method is used to store the velocity and pressure variables at different grid points respectively, thus avoiding the coupling between the pressure field and the velocity field; on the staggered grid, the velocity variables are stored at the corners of the grid, while the pressure variables are stored at the centers of the grid. Finally, the surfactant concentration distribution is updated using the surfactant concentration equation, and the droplet surface shape is updated using the droplet surface evolution equation until the droplet morphology no longer changes significantly.

[0088] Through the above steps, the process of a droplet falling onto a substrate can be simulated, and its spreading behavior can be observed; the evaporation process of the droplet can also be simulated, and its morphological changes can be observed; the dissolution and adsorption behaviors of the surfactant on the droplet surface and inside the liquid, as well as its influence on the surface tension, can also be simulated. Finally, when the droplet morphology no longer changes significantly, the droplet is considered to reach a steady state. The steady-state morphology of the droplet is output, including parameters such as the shape, size, and contact angle of the droplet.

[0089] In this embodiment, through the diffusion domain simulation method, the behavior of droplets on the substrate during the inkjet printing process can be accurately simulated, and the steady-state morphology of the droplets can be obtained; combined with the pressure-stabilized splitting method, staggered grid finite difference, and CPU parallel multigrid algorithm, the droplet motion, surfactant diffusion, and interface evolution equations can be effectively solved, and the stability and accuracy of the numerical solutions can be guaranteed.

[0090] Step S300, determine the surface flatness of the droplet according to the droplet state.

[0091] In this embodiment, the phase field method is used to simulate the spreading process of the droplet on the substrate. After obtaining the final state of the droplet on the substrate, the contour lines of the phase field function are drawn, and the contour lines of the phase field function represent the interface of the droplet. In order to quantify the flatness of the droplet surface, an optimal fitting straight line can be fitted according to the contour lines of the phase field function. By calculating the sum of the squares of the distances between the droplet surface and the optimal fitting straight line and taking its square root to obtain the error degree, the flatness of the droplet surface can be effectively evaluated.

[0092] In this embodiment, the surface flatness of the droplet is calculated through the droplet state. The surface flatness of the droplet directly affects the uniformity of the final thin film. By evaluating the flatness of the droplet, the thickness distribution and surface roughness of the thin film can be predicted, thereby evaluating the film formation quality.

[0093] Step S400: Determine the evaluation result of the first inkjet printing scheme according to the surface flatness of the droplet.

[0094] In this embodiment, the advantages and disadvantages of the inkjet printing scheme can be evaluated according to the surface flatness of the droplet. The evaluation result can be represented in the form of grade division, scoring, etc., which can more intuitively reflect the advantages and disadvantages of the droplet surface flatness and facilitate the comparison and optimization of the schemes. The evaluation result can also include parameters such as the final state of the droplet on the substrate, the shape, size, contact angle of the droplet, or a recommended scheme obtained by optimizing some printing parameters based on the input inkjet printing scheme to be evaluated, which is not limited herein.

[0095] In one implementation manner of this embodiment, the evaluation result of the inkjet printing scheme can be represented in the form of scoring. Specifically, the inkjet printing scheme can be comprehensively scored according to indicators such as the surface flatness of the droplet, the uniformity of the surfactant concentration distribution, the evaporation rate, and the film-forming quality. The scoring method can be calculated by weighted average or other custom methods, which is not limited herein.

[0096] In another implementation manner of this embodiment, each scoring indicator corresponds to at least one printing parameter, and each printing parameter affects at least one scoring indicator, thereby affecting the score of the final inkjet printing scheme. In the specific scoring criteria, the score of each printing parameter can also be evaluated first, and the score of the scoring indicator affected by it can be obtained according to the score of each printing parameter, and then the final score of the inkjet printing scheme can be calculated according to the scores of the scoring indicators; or the score of the inkjet printing scheme can be directly calculated according to methods such as linear weighting, nonlinear weighting, or analytic hierarchy process. The specific scoring method can be designed according to actual application requirements, which is not limited herein. When the score of the inkjet printing scheme is poor, the inkjet printing scheme can be optimized by adjusting the printing parameters with lower scores.

[0097] In this embodiment, by dividing the evaluation result into different grades or giving a score, the advantages and disadvantages of the droplet surface flatness can be more intuitively reflected, and the film-forming effects of different schemes can be intuitively compared according to the grade or score; the final state of the droplet on the substrate, such as shape, size, contact angle, etc., can be more comprehensively understood, so as to better analyze the film-forming process and further analyze the influence degree of different parameters on the droplet film-forming effect; based on the evaluation result, more optimal printing parameters can be recommended, thereby reducing the experimental cost and time and improving the production efficiency and product quality.

[0098] In some embodiments, step S200 may include but is not limited to steps S210 to S220:

[0099] Step S210, construct an inkjet printing model based on the multiple printing parameters, where the inkjet printing model is used to simulate the formation process of the liquid in inkjet printing and the spreading process of the liquid droplets on the substrate;

[0100] Step S220, perform inkjet printing simulation on the multiple printing parameters through the inkjet printing model to obtain the droplet state of the first inkjet printing scheme.

[0101] In this embodiment, an inkjet printing model is constructed based on multiple printing parameters. The inkjet printing model can be obtained by coupling the surfactant concentration diffusion equation describing the diffusion on the droplet surface, the phase field equation describing the droplet surface, the hydrodynamic equation describing the droplet flow field, and the moving contact line dynamics equation describing the dynamic change of the contact line between the droplet and the substrate based on the diffusion zone method. Among them, the surfactant concentration diffusion equation is used to describe the diffusion and adsorption behavior of the surfactant on the droplet surface and inside the liquid; the phase field equation is used to describe the morphological evolution of the droplet surface, connect the two fluids, and consider the influence of the surfactant on the surface tension; the hydrodynamic equation is used to describe the motion law of the droplet, including mass conservation and momentum balance; the moving contact line dynamics equation is used to describe the dynamic change of the contact line between the droplet and the substrate, considering the interfacial tension, fluid flow, and slip effect. Then, by introducing a smooth interface function describing the boundary, the original equation is modified and the whole model is embedded in a larger regular region for calculation using a standard fast solver.

[0102] After obtaining the inkjet printing model, perform simulation on the multiple printing parameters in the inkjet printing scheme to be evaluated through the inkjet printing model to obtain the droplet state corresponding to the inkjet printing scheme to be evaluated, and quickly achieve the accurate simulation of the behavior of the droplets in the inkjet printing process.

[0103] In this embodiment, by constructing an inkjet printing model that couples multiple equations and combining the diffusion zone method for numerical solution, while maintaining high-precision simulation, the influence of complex structures on the calculation efficiency is reduced, and the operability and efficiency of numerical solution are improved.

[0104] In some embodiments, step S210 may include but is not limited to steps S211 to S216:

[0105] Step S211, simulate the shape of the substrate and the inkjet printing droplets through a phase field function, and use the phase field method to describe the spreading process of the droplets on the substrate;

[0106] Step S212, simulate the evaporation process on the droplet surface according to the evaporation parameters;

[0107] Step S213: Simulate the dissolution rate of the surfactant within the droplet and the concentration distribution of the surfactant on the droplet surface based on the surface thickness of the droplet and the diffusion coefficient of the surfactant.

[0108] Step S214: Simulate the mass conservation and momentum balance of the droplet during the printing process based on the density, viscosity, and surface tension of the droplet among the physical properties of the droplet.

[0109] Step S215: Simulate the roughness of the substrate and the movement process of the contact line between the droplet and the substrate among the substrate interface characteristics based on the slip length.

[0110] Step S216: Adopt the diffusion domain method, simulate the substrate structure through the interface function, and extend the computational domain to a regular geometric region to obtain the inkjet printing model.

[0111] In this embodiment, the phase field function can be used to simulate the substrate shape and the droplet shape respectively. As Figure 3a - Figure 3d shown, the substrate shape can include but is not limited to an inclined plane structure, a square structure, a rectangular structure, a cylindrical structure, and is not limited herein.

[0112] In this embodiment, the phase field function takes different values inside the substrate and the droplet and smoothly transitions at the interface, thereby continuously describing the droplet surface. The phase field method can also be used to describe the morphological evolution of the droplet surface, including behaviors such as the expansion, spreading, and contraction of the droplet. At the same time, the interactions between the droplet surface, the surfactant, and the substrate will also be considered, such as the interfacial tension, the surfactant concentration distribution, and the substrate roughness, so as to accurately simulate the interfacial evolution process of the droplet.

[0113] In this embodiment, the evaporation process of the droplet surface can be simulated according to the evaporation parameters such as the temperature, humidity, and evaporation rate of the environment where the droplet is located. The evaporation process will also affect the droplet morphology and the surfactant concentration distribution.

[0114] In this embodiment, the dissolution rate of the surfactant in the droplet and the concentration distribution on the droplet surface can be simulated based on the surface thickness of the droplet and the diffusion coefficient of the surfactant. The diffusion of the surfactant will affect the surface tension of the droplet, thereby affecting the spreading behavior of the droplet.

[0115] In this embodiment, the mass conservation and momentum balance of the droplet during the printing process can be simulated based on the physical properties such as the density, viscosity, and surface tension of the droplet. These physical properties will affect the flow behavior and spreading speed of the droplet.

[0116] In this embodiment, the roughness of the substrate can be simulated based on the slip length. The slip length will affect the contact line between the droplet and the substrate and the spreading speed.

[0117] In this embodiment, a smooth interface function can be introduced to simulate the substrate structure using the interface function and extend the computational domain to a regular geometric region. The diffuse domain method can simplify the calculation process and improve the calculation efficiency.

[0118] Specifically, the droplet surface can be described by the phase field method, and a physical model of droplet motion with surfactants can be derived from the energy variational principle. This model takes into account the morphological evolution of the droplet surface, the influence of surfactants on surface tension, and the interaction between the droplet and the substrate, thereby accurately simulating the processes of droplet spreading, wetting, and interface evolution.

[0119]

[0120]

[0121] Among them, φ is the phase field variable used to describe the interface. The two fluids are represented by 1 and -1 respectively. φ is a smooth function connecting the two fluids. u is the velocity of the fluid, ψ is the concentration of the surfactant, Ex is the dissolution rate of the surfactant in the fluid, and Cn is the interface thickness introduced by the phase field model. φ is a function of space and time, specifically defined as φ(x, y, z, t), where x, y, z are spatial coordinates and t is time. φ t is the time derivative, representing the change of φ with time. is the transport term of φ along the fluid velocity field, representing the motion brought to φ by fluid motion. is the reciprocal of the spatial diffusion coefficient of φ. μ φ is the chemical potential energy. Equation (2) is the variational expression of the free energy with respect to φ, representing the change of φ when the free energy dissipates. Equations (1) and (2) describe the equation of the interface following fluid motion and its own diffusion and adsorption.

[0122] The formula used to describe the surfactant is:

[0123]

[0124] Among them, ψ is the concentration of the surfactant, which satisfies the transport equation following fluid motion and conforms to the driven chemical potential diffusion in Equation (4). ψ is a function of space and time, specifically defined as ψ(x, y, z, t), where x, y, z are spatial coordinates and t is time. ψ t is the time derivative, representing the change of ψ with time. is the transport term of ψ along the fluid velocity field, representing the motion brought to ψ by fluid motion. is the reciprocal of the spatial diffusion coefficient of ψ. μ ψ is the chemical potential energy. Equation (4) is the variational expression of the free energy with respect to ψ, representing the change of ψ when the free energy dissipates. The and From the phase field variables, by introducing the dissolution rate Ex of the active agent, the dissolution rate of the active agent in the liquid and the concentration distribution of the active agent on the droplet surface are described, so as to accurately simulate the dissolution change and interfacial adsorption behavior of the active agent on the droplet surface and inside the liquid.

[0125] In addition, the motion of the fluid is described by the incompressible equation to ensure the mass conservation and momentum balance of the droplet during the printing process. Specifically as follows:

[0126]

[0127] Among them, ρ is the density of the fluid, Re is the Reynolds number, representing the ratio of the inertial force to the viscous force magnitude, and We is the Weber number, representing the ratio of the inertial force to the surface tension effect. Equation (5) is the fluid momentum equation, and the first term on the left end is the fluid transport term, the second term on the left end is the flow rate caused by the density change, the third term on the left end is the pressure gradient, the first term on the right end is the viscous dissipation term, and the second term on the right end is the surface tension term between the two fluids. Equation (6) describes the incompressible condition of the fluid, ensuring that the volume of the droplet does not change during the flow process and maintaining the mass conservation of the fluid. By using the incompressible equation to simulate the mass conservation and momentum balance of the droplet, the incompressible equation describes the hydrodynamic process, ensuring the mass conservation and momentum balance of the droplet during the printing process; by introducing the density, Reynolds number and Weber number of the fluid, the incompressible condition of the fluid is described, ensuring that the volume of the droplet does not change during the flow process and maintaining the mass conservation of the fluid.

[0128] When the droplet begins to spread after falling onto the substrate structure, a contact line is formed between the droplet surface and the solid region, and the Young's contact angle is generated by the tension between the interface and the solid-liquid surface. The Young's contact angle is the angle formed when the liquid contacts the solid surface, and this angle is crucial for understanding phenomena such as the wettability, adsorption and adhesion of the liquid on the solid surface. During the dynamic process of droplet spreading, the contact angle will deviate with the evolution of the interface and the motion of the fluid. This process can be described by Equation (7) and Equation (8), in which the interaction force between the droplet and the substrate, the surface tension and the dynamic flow effect are considered, and then the change law of the contact angle is described.

[0129]

[0130] Among them, γ wf (φ) is the solid-liquid boundary energy, interpolated by the interface function φ, γ 1 , γ 2are the two liquid-solid interfacial tensions, and θ s is the Young's contact angle. The condition of Equation (7) indicates that the contact angle of the interface satisfies the Young's contact angle.

[0131] For a moving contact line, general Navier boundary conditions are introduced to accurately describe the motion of the contact line. These boundary conditions consider the slip effect between the liquid droplet surface and the solid surface, can accurately simulate the evolution of the contact line during the dynamic process, and further reveal the variation law of the contact angle during droplet spreading. Through these conditions, the interaction of the interfacial tension of the moving droplet on the substrate can be effectively captured.

[0132]

[0133] u s = u τ - u w (10)

[0134] where l s is the slip length, which is used to describe the roughness of the solid surface. The larger it is, the greater the velocity slip. u s is the slip velocity, which is equal to the tangential velocity u τ minus the velocity u w of the solid. By introducing the slip length to describe the roughness of the solid surface, the motion of the contact line can be accurately described, and the variation law of the contact angle during droplet spreading can be further revealed. As Figure 4 shown, the coating can change the hydrophilicity and hydrophobicity. In experiments, this parameter can be adjusted by coating or the design of microstructures, so as to accelerate or slow down the moving speed of the contact line, and then change the spreading speed of the droplet. By adjusting these factors, the spreading process of the droplet and the dynamic change of the contact angle can be accurately controlled.

[0135] The evaporation rate is closely related to the humidity in the air. Here, it is assumed that the humidity in the external environment of the droplet remains consistent. Therefore, a simple relationship between the interfacial evaporation velocity and the humidity can be obtained, as shown in Equation (11) specifically:

[0136] u = k c (c 2 - 1) (11)

[0137] where c represents the humidity, u is the interfacial moving velocity caused by evaporation, and k c is the evaporation rate. By introducing the influence of humidity on the evaporation rate, the effect of humidity on the droplet evaporation process is effectively added to the phase field model and further integrated into the interfacial moving equation of Equation (1). In this way, the evaporation process on the droplet surface can be dynamically simulated, and the evolution of the droplet shape under different humidity conditions and the influence of the evaporation rate on droplet spreading can be described.

[0138] As shown Figure 5 In the inkjet printing process, the droplets first fall onto the substrate and then spread on the substrate surface. To optimize the spreading process of the droplets, different substrate structures can be designed, such as the ramp interfaces on both sides or the columnar structures on the substrate. However, these complex structures pose great challenges to numerical simulation. To solve this problem, the diffusion domain method is adopted in this embodiment. By introducing a smooth interface function to describe the boundary, the original equations are modified, and the entire model is embedded into a larger regular domain, so that the standard fast solver can be applied. Exemplarily, for Equation (1), by introducing the interface function ξ (taking the value of 0 in the solid region and 1 in the liquid region), the modified equation is obtained. This function can describe the shape of the substrate boundary and smoothly transition to the internal region. Among them, the value of the interface function is as shown in Equation (12):

[0139]

[0140] where r(x,t) represents the distance to the solid boundary, and ε ξ is an artificial interface, which can be set according to the accuracy requirements of the actual problem and takes a value equal to a small number. Ω is the entire regular domain. In this way, while maintaining high-precision simulation, the influence of complex structures on the computational efficiency is reduced, and the operability and efficiency of numerical solution are improved.

[0141] Multiply the smooth interface function by the relevant terms in the original equation and embed the model into a larger regular domain. Exemplarily, extend Equation (1) and Equation (2) to the regular domain through the solid interface function ξ to obtain Equation (13) and Equation (14):

[0142]

[0143] Among them, Equation (15) is the equation that embeds the boundary conditions in Equation (8) into the body. Figure 6 shows the use of the diffusion domain method to extend the Figure 3a ramp structure in to the entire rectangular regular domain by this method.

[0144] In this embodiment, by constructing an inkjet printing model considering multiple printing parameters, the behavior of droplets in the inkjet printing process can be accurately simulated. The model considers a variety of printing parameters, including droplet shape, substrate shape, evaporation parameters, surfactant properties, droplet physical properties, and substrate interface properties, etc., and can accurately simulate the spreading, evaporation, and surfactant diffusion processes of droplets in the inkjet printing process. The diffusion domain method can transform the computational problem of complex structures into a computational problem of regular domains, thereby simplifying the computational process and improving the computational efficiency.

[0145] In some embodiments, step S300 may include but is not limited to steps S310 to S330:

[0146] Step S310, representing the droplet state using the contour line of the phase field function, wherein the position where the contour line of the phase field function is 0 represents the surface of the droplet;

[0147] Step S320, calculating a target fitting line according to the position points on the surface of the droplet, and the sum of the perpendicular distances from the target fitting line to each position point on the surface of the droplet is the smallest;

[0148] Step S330, determining the flatness of the surface of the droplet according to the deviation between the surface of the droplet and the target fitting line.

[0149] The phase field method is a numerical method for describing the evolution of multiphase fluid interfaces. In the phase field model, a function φ called the phase field variable is introduced, and its value varies between two fluids. For example, it is 1 inside the droplet and -1 on the substrate.

[0150] In this embodiment, the droplet state can be represented using the contour line of the phase field function. The contour line of the phase field function φ, that is, the line composed of points with equal φ values, can be used to represent the interface between the droplet and the substrate. When φ = 0, it represents the boundary where the droplet contacts the substrate, that is, the surface of the droplet. By drawing the contour line of φ = 0, the shape and position of the droplet on the substrate can be clearly shown.

[0151] Then, calculate the best fitting line based on the position points on the surface of the droplet. Using the least squares method or other fitting methods, fit a line as the best fitting line according to the selected position points, so that the sum of the perpendicular distances from this line to each position point is minimized. Finally, evaluate the flatness of the droplet surface by comparing the actual position of the droplet surface and the position of the target fitting line.

[0152] In this embodiment, the shape and position of the droplet surface can be accurately described by using the contour line of the phase field function, avoiding the errors caused by the blurred droplet edge or insufficient resolution in the traditional method; by the perpendicular distance between the fitting line and the actual position points on the droplet surface, the deviation of each point can be accurately quantified, and then the flatness of the droplet surface during the inkjet printing process can be evaluated.

[0153] In some embodiments, step S330 may include but is not limited to steps S331 to S334:

[0154] Step S331, respectively obtaining the distance from each position point on the surface of the droplet to the target fitting line;

[0155] Step S332, performing a sum of squares operation on the obtained distances to obtain a target sum of squares;

[0156] Step S333: Take the square root of the target sum of squares as the degree of error.

[0157] Step S334: Perform flatness evaluation based on the degree of error to obtain the flatness of the surface of the droplet.

[0158] In this embodiment, all position points representing the surface of the droplet are extracted from the contour lines of the phase field function. For each position point on the surface of the droplet, calculate its perpendicular distance to the target fitting line; square the distance values of all position points, and then add these squared values to obtain a sum, which is called the target sum of squares; take the square root of the target sum of squares to obtain a value, which is called the degree of error E; evaluate the flatness of the surface of the droplet according to the magnitude of the degree of error E. The smaller the degree of error, the flatter the surface of the droplet and the smaller the deviation from the target fitting line.

[0159] In this embodiment, by calculating the distance from each position point on the surface of the droplet to the target fitting line, performing a sum of squares operation, and taking the square root of the result as the degree of error for flatness evaluation, the flatness of the surface of the droplet can be quantified as a value, which is convenient for comparison and analysis.

[0160] In some embodiments, after step S400, it may further include but is not limited to steps S500 to S700:

[0161] Step S500: Determine whether the score in the evaluation result of the first inkjet printing scheme exceeds a preset threshold.

[0162] Step S600: If the score in the evaluation result of the first inkjet printing scheme exceeds the preset threshold, output the evaluation result of the first inkjet printing scheme.

[0163] Step S700: If the score in the evaluation result of the first inkjet printing scheme does not exceed the preset threshold, determine the printing parameters to be optimized in the first inkjet printing scheme and the optimization interval corresponding to each printing parameter to be optimized, and output the evaluation result of the first inkjet printing scheme, the printing parameters to be optimized, and the optimization interval corresponding to each printing parameter to be optimized.

[0164] In this embodiment, it is judged whether the inkjet printing scheme to be evaluated meets the established technical requirements and performance indicators according to the score in the evaluation result of the inkjet printing scheme to be evaluated. Specifically, a threshold can be set as an index to measure whether the inkjet printing scheme to be evaluated meets the requirements. If the score of the inkjet printing scheme to be evaluated is higher than the preset threshold, it means that the inkjet printing scheme meets the requirements. Among them, the preset threshold can be set and adjusted according to actual production requirements and is not limited here.

[0165] If the score in the evaluation result of the inkjet printing solution exceeds the preset threshold, it means that the inkjet printing solution meets the preset requirements, and then the evaluation result of the inkjet printing solution can be directly output for the user's reference. Among them, the evaluation result of the inkjet printing solution includes, but is not limited to, parameters such as error degree, score, and droplet steady state morphology, which are not limited here.

[0166] If the score in the evaluation result of the inkjet printing solution does not exceed the preset threshold, it means that the inkjet printing solution does not meet the preset requirements. Then, the printing parameters that need to be adjusted and optimized can be marked and provided to the user. At the same time, the adjustable range of each printing parameter can be generated according to the simulation result for the user's reference. Finally, the evaluation result, the printing parameters to be optimized, and the optimization range corresponding to each printing parameter to be optimized are output. Through the above steps, not only can the current printing solution be evaluated, but also specific guidance can be provided for improving the printing quality, thereby helping engineers or researchers quickly identify the problems and adjust the printing parameters accordingly to achieve the required printing quality.

[0167] In one implementation manner of this embodiment, the printing parameters with lower scores can be obtained according to the evaluation result as the printing parameters to be optimized, and the optimization range of the printing parameters to be optimized can be obtained according to the scoring criteria. Exemplarily, if the initial concentration of the surfactant is relatively high, resulting in a lower score of the inkjet printing solution, then the initial concentration of the surfactant is used as one of the printing parameters to be optimized in the inkjet printing solution, and the optimization range of the initial concentration of the surfactant is generated by means of past experimental records or predicting experimental results using numerical simulation techniques, etc., so as to improve the score in the evaluation result of the inkjet printing solution.

[0168] This embodiment sets a minimum quality standard for the inkjet printing solution through a preset threshold, which can quickly identify which printing solutions have met the requirements and screen out the inkjet printing solutions that reach or exceed the quality standard; for the inkjet printing solutions that do not reach the threshold, marking the printing parameters to be optimized and providing specific optimization ranges can reduce the number of experiments required and speed up the process of finding the appropriate printing parameters; it can also flexibly set the threshold and optimization strategy according to different application scenarios and specific requirements to ensure the wide applicability of the method.

[0169] In some embodiments, after step S700, it may further include, but is not limited to, steps S701 to S708:

[0170] Step S701, taking the first inkjet printing solution as the current inkjet printing solution, taking the printing parameters to be optimized of the first inkjet printing solution as the target parameters, and taking the optimization range corresponding to the printing parameters to be optimized as the target range;

[0171] Step S702: Regenerate multiple temporary inkjet printing schemes according to the target parameters of the current inkjet printing scheme and the target intervals corresponding to the target parameters;

[0172] Step S703: Conduct inkjet printing simulation on each of the temporary inkjet printing schemes to obtain the evaluation results corresponding to each of the temporary inkjet printing schemes;

[0173] Step S704: Take the temporary inkjet printing scheme corresponding to the evaluation result with the highest score among the evaluation results corresponding to the multiple temporary inkjet printing schemes as the target inkjet printing scheme;

[0174] Step S705: If the score in the evaluation result of the target inkjet printing scheme exceeds the preset threshold, output the evaluation result of the target inkjet printing scheme;

[0175] Step S706: If the score in the evaluation result of the target inkjet printing scheme does not exceed the preset threshold, determine the printing parameters to be optimized in the target inkjet printing scheme and the optimization intervals corresponding to each of the printing parameters to be optimized;

[0176] Step S707: Take the target inkjet printing scheme as the current inkjet printing scheme, take the printing parameters to be optimized in the target inkjet printing scheme as the target parameters, and take the optimization intervals corresponding to the printing parameters to be optimized as the target intervals, and execute the step of regenerating multiple temporary inkjet printing schemes according to the target parameters of the current inkjet printing scheme and the target intervals corresponding to the target parameters;

[0177] Step S708: If the score in the evaluation result of the target inkjet printing scheme exceeds the preset threshold, output the evaluation result of the target inkjet printing scheme.

[0178] In the process of evaluating the inkjet printing scheme, if the score of the initial scheme does not exceed the preset threshold, and after marking the printing parameters to be optimized and generating the corresponding optimization intervals, the method of further introducing multiple temporary inkjet printing schemes for simulation evaluation can significantly improve the efficiency of finding the optimal scheme.

[0179] In this embodiment, based on the previously determined printing parameters to be optimized and their optimization intervals, a plurality of different parameter combinations are generated to form a plurality of temporary inkjet printing schemes. Then, the constructed inkjet printing model is used to simulate each temporary inkjet printing scheme to simulate the formation, spreading, and final state of the droplets. And according to the output of the simulation, the score of each temporary scheme is calculated. By comparing the evaluation results of a plurality of temporary inkjet printing schemes, the scheme with the highest score is selected as the target inkjet printing scheme. If the score of the target inkjet printing scheme is greater than the preset threshold, it means that the target inkjet printing scheme meets the preset requirements and the corresponding evaluation result can be directly output for the user's reference; if the score of the target inkjet printing scheme is not greater than the preset threshold, it means that the target inkjet printing scheme does not meet the preset requirements, then the target inkjet printing scheme can be used as the starting point for the next round of iteration, and by adjusting the parameter range, the scheme is gradually optimized until the score of the target inkjet printing scheme exceeds the preset threshold.

[0180] Through continuous iterative optimization in this embodiment, it is ensured that the finally selected inkjet printing scheme can meet or exceed the set quality standards; each iteration can more precisely adjust the key parameters, gradually narrow the optimization interval, and increase the possibility of finding the optimal solution; by using simulation instead of actual experiments, the material, time, and labor costs required for physical experiments are greatly reduced; by using simulation technology to quickly evaluate a large number of temporary schemes, the best scheme can be screened out in a relatively short time, reducing the time cost of trial and error.

[0181] Figure 7 It is the technical roadmap of the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing provided by the embodiment of the present application, and the specific execution process is as follows:

[0182] 1. Model construction:

[0183] Based on the diffusion region method, the substrate shape is described, and the diffusion equation of the surfactant concentration on the droplet surface, the phase field equation of the droplet surface, the hydrodynamic equation of the droplet flow field, and the dynamic equation of the moving contact line between the droplet surface and the substrate are coupled to obtain a complete coupling equation for simulating the whole process of droplet evaporation deformation and the dynamics of the moving contact line in the substrate.

[0184] 2. Model parameter input: Substrate shape, droplet shape, physical properties of the droplet (density, viscosity, and surface tension), initial concentration of the surfactant, diffusion coefficient of the surfactant, substrate interface characteristics (roughness, coating parameters, and microstructures), and evaporation parameters.

[0185] Extract the phase field function from the experimental images or generate it through analytical expression to simulate the substrate shape; extract the phase field function from the experimental images or generate it through analytical expression to simulate the droplet shape; calculate the concentration distribution of the surfactant on the droplet surface based on the initial dosage of the surfactant added in the experiment to obtain the initial concentration of the surfactant; determine the diffusion rate and the corresponding diffusion coefficient of the surfactant on the droplet surface according to the type of the surfactant; the roughness is the average roughness or the fluctuation characteristic parameter of the interface, the coating parameter is the thickness or the material property of the substrate coating, and the fine structure is the microscopic morphological feature of the substrate surface; determine the evaporation conditions according to the humidity of the environment where the droplet is located to obtain the evaporation parameters.

[0186] 3. Model calculation: Adopt the pressure-stabilized splitting method, the staggered grid finite difference method and the CPU parallel multi-grid algorithm to obtain high-precision and high-resolution numerical simulation results, simulate the evaporation kinetics process of the droplet on the substrate, and give the final steady-state properties of the droplet on the substrate.

[0187] 4. Model output: The flatness of the droplet steady-state interface. First, calculate the flatness evaluation of the best-fit straight interface based on the positions on the droplet surface; then, calculate the square root of the sum of the squares of the distances from each point on the droplet surface (phase field variable contour line) to the fit line; finally, quantify the flatness of the droplet steady-state interface through b. The smaller b is, the higher the flatness.

[0188] In the embodiment of the present application, an inkjet printing scheme including multiple printing parameters is obtained, and an inkjet printing model is constructed based on the multiple printing parameters. This model uses the phase field method to simulate the spreading process of the droplet on the substrate and combines the diffusion domain method to expand the calculation area; in addition, the evaporation process on the droplet surface, the dissolution rate of the surfactant in the droplet and its surface concentration distribution, and the movement process of the contact line between the droplet and the substrate are also considered; through this model, the whole process of the droplet from formation to final deposition on the substrate can be accurately simulated; the droplet state is represented by the contour line of the phase field function, and the position where the contour line is 0 represents the droplet surface. By calculating the distance from each position point to the target fit line and performing the sum of squares operation, the square root of the result is used as the error degree to quantify the flatness of the droplet surface. If the evaluation result does not reach the preset threshold, mark the parameters to be optimized and generate the optimization interval, and optimize the printing scheme through iterative simulation until an inkjet printing scheme that meets the preset threshold and the corresponding evaluation result are output. Through automated simulation and iterative optimization, the accuracy of the printing parameters and the printing quality are improved, the experimental cost is reduced, and the continuous improvement of the inkjet printing scheme is ensured until the quality standard is met. The embodiment of the present application can quickly evaluate the key parameters affecting the film formation uniformity in the inkjet printing process, and effectively suppress the coffee ring effect and improve the performance of the OLED device by optimizing the parameters and the substrate structure.

[0189] Please refer to Figure 8, the embodiment of the present application further provides a diffusion domain simulation device 800 for suppressing the coffee ring effect in OLED inkjet printing, which can implement the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing. The device includes:

[0190] An acquisition module 10, which acquires a first inkjet printing scheme to be evaluated, and the first inkjet printing scheme includes a plurality of printing parameters;

[0191] A simulation module 20, which performs inkjet printing simulation according to the plurality of printing parameters to obtain the droplet state of the first inkjet printing scheme, and the droplet state is the final state of the droplet on the substrate;

[0192] A calculation module 30, which determines the surface flatness of the droplet according to the droplet state;

[0193] An evaluation module 40, which determines the evaluation result of the first inkjet printing scheme according to the surface flatness of the droplet.

[0194] In some embodiments, the simulation module 20 may include:

[0195] A model construction sub-module, which is used to construct an inkjet printing model based on the plurality of printing parameters, and the inkjet printing model is used to simulate the formation process of droplets and the spreading process of the droplets on the substrate in inkjet printing; at least two of the plurality of printing parameters include substrate shape, shape of inkjet printing droplets, physical properties of droplets, initial concentration of surfactant, diffusion coefficient of surfactant, substrate interface characteristics, and evaporation parameters;

[0196] A simulation sub-module, which is used to perform inkjet printing simulation on the plurality of printing parameters through the inkjet printing model to obtain the droplet state of the first inkjet printing scheme.

[0197] In some embodiments, the model construction sub-module may include:

[0198] A phase field simulation unit, which is used to simulate the substrate shape and the shape of the inkjet printing droplets through a phase field function, and describe the spreading process of the droplets on the substrate by using the phase field method;

[0199] An evaporation simulation unit, which is used to simulate the evaporation process on the surface of the droplet according to the evaporation parameters;

[0200] A surfactant simulation unit, which is used to simulate the dissolution rate of the surfactant in the droplet and the concentration distribution of the surfactant on the surface of the droplet according to the surface thickness of the droplet and the diffusion coefficient of the surfactant;

[0201] A dynamic simulation unit for simulating the mass conservation and momentum balance of the droplet during the printing process according to the density of the droplet, the viscosity of the droplet, and the surface tension of the droplet among the physical properties of the droplet;

[0202] A contact line simulation unit for simulating the roughness of the substrate and the movement process of the contact line between the droplet and the substrate in the substrate interface characteristics according to the slip length;

[0203] A substrate structure simulation unit for simulating the substrate structure by using the diffusion domain method through an interface function and extending the calculation region to a regular geometric region to obtain the inkjet printing model.

[0204] In some embodiments, the calculation module 30 may include:

[0205] A contour calculation sub-module for representing the droplet state by using the contour of the phase field function, wherein the position where the contour of the phase field function is 0 represents the surface of the droplet;

[0206] A straight line fitting sub-module for calculating a target fitting straight line according to the position points on the surface of the droplet, and the sum of the perpendicular distances between the target fitting straight line and the position points on the surface of each droplet is the smallest;

[0207] A flatness calculation sub-module for determining the surface flatness of the droplet according to the deviation between the surface of the droplet and the target fitting straight line.

[0208] In some embodiments, the flatness calculation sub-module may include:

[0209] A distance acquisition unit for respectively acquiring the distances from each position point on the surface of the droplet to the target fitting straight line;

[0210] A sum of squares operation unit for performing a sum of squares operation on the acquired distances to obtain a target sum of squares;

[0211] An error degree calculation unit for taking the square root of the target sum of squares as the error degree;

[0212] A flatness evaluation unit for performing flatness evaluation according to the error degree to obtain the surface flatness of the droplet.

[0213] In some embodiments, the evaluation module 40 may further include:

[0214] A judgment sub-module for judging whether the score in the evaluation result of the first inkjet printing scheme exceeds a preset threshold;

[0215] A first output sub-module, configured to output the evaluation result of the first inkjet printing solution if the score in the evaluation result of the first inkjet printing solution exceeds a preset threshold;

[0216] A second output sub-module, configured to determine the printing parameters to be optimized in the first inkjet printing solution and the optimization interval corresponding to each printing parameter to be optimized if the score in the evaluation result of the first inkjet printing solution does not exceed the preset threshold, and output the evaluation result of the first inkjet printing solution, the printing parameters to be optimized, and the optimization interval corresponding to each printing parameter to be optimized.

[0217] In some embodiments, the second output sub-module may further include:

[0218] A first iteration unit, configured to use the first inkjet printing solution as the current inkjet printing solution, use the printing parameters to be optimized in the first inkjet printing solution as the target parameters, and use the optimization interval corresponding to the printing parameter to be optimized as the target interval;

[0219] A solution generation unit, configured to regenerate a plurality of temporary inkjet printing solutions according to the target parameters of the current inkjet printing solution and the target interval corresponding to the target parameters;

[0220] A simulation unit, configured to perform inkjet printing simulation on each temporary inkjet printing solution to obtain the evaluation result corresponding to each temporary inkjet printing solution;

[0221] A second iteration unit, configured to use the temporary inkjet printing solution corresponding to the evaluation result with the highest score among the evaluation results corresponding to the plurality of temporary inkjet printing solutions as the target inkjet printing solution;

[0222] A first output unit, configured to output the evaluation result of the target inkjet printing solution if the score in the evaluation result of the target inkjet printing solution exceeds the preset threshold;

[0223] An optimization unit, configured to determine the printing parameters to be optimized in the target inkjet printing solution and the optimization interval corresponding to each printing parameter to be optimized if the score in the evaluation result of the target inkjet printing solution does not exceed the preset threshold;

[0224] A third iteration unit, configured to use the target inkjet printing solution as the current inkjet printing solution, use the printing parameters to be optimized in the target inkjet printing solution as the target parameters, and use the optimization interval corresponding to the printing parameter to be optimized as the target interval, and perform the step of regenerating a plurality of temporary inkjet printing solutions according to the target parameters of the current inkjet printing solution and the target interval corresponding to the target parameters;

[0225] A second output unit, configured to output the evaluation result of the target inkjet printing solution if the score in the evaluation result of the target inkjet printing solution exceeds a preset threshold.

[0226] The specific implementation manner of the diffusion domain simulation device for suppressing the coffee ring effect in OLED inkjet printing is basically the same as the specific embodiment of the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing, and will not be described in detail herein.

[0227] An embodiment of the present application further provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing. The electronic device can be any intelligent terminal including a tablet computer, an in-vehicle computer, etc.

[0228] Please refer to Figure 9 , Figure 9 which schematically shows the hardware structure of an electronic device in another embodiment. The electronic device includes:

[0229] A processor 901, which can be implemented in a general-purpose CPU (Central Processing Unit), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits, etc., and is used to execute relevant programs to implement the technical solutions provided by the embodiments of the present application;

[0230] A memory 902, which can be implemented in the form of a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM), etc. The memory 902 can store an operating system and other application programs. When implementing the technical solutions provided by the embodiments of the present specification through software or firmware, the relevant program codes are stored in the memory 902 and are called by the processor 901 to execute the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing in the embodiments of the present application;

[0231] An input / output interface 903, configured to implement information input and output;

[0232] A communication interface 904, configured to implement communication interaction between this device and other devices, and can implement communication through a wired manner (such as USB, network cable, etc.) or through a wireless manner (such as mobile network, WIFI, Bluetooth, etc.);

[0233] A bus 905 transmits information between various components of the device (such as a processor 901, a memory 902, an input / output interface 903, and a communication interface 904).

[0234] Among them, the processor 901, the memory 902, the input / output interface 903, and the communication interface 904 are communicatively connected to each other inside the device through the bus 905.

[0235] An embodiment of the present application also provides a computer-readable storage medium storing a computer program, which when executed by a processor implements the above-mentioned diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing.

[0236] As a non-transitory computer-readable storage medium, the memory can be used to store non-transitory software programs and non-transitory computer-executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0237] The diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing, the diffusion domain simulation device for suppressing the coffee ring effect in OLED inkjet printing, the electronic device, and the storage medium provided by the embodiments of the present application perform inkjet printing simulation on multiple key printing parameters in the inkjet printing scheme input by the user, and obtain the final state of the droplets on the substrate in the inkjet printing scheme according to the simulation results; determine the surface flatness of the droplets according to the final state of the droplets; determine the evaluation result of the inkjet printing scheme according to the surface flatness, and the higher the surface flatness, the better the inkjet printing scheme. The present application uses numerical simulation technology to quickly evaluate the film-forming effect of the inkjet printing scheme, and then optimizes the inkjet printing effect by adjusting multiple key printing parameters in the inkjet printing scheme, and improves the uniformity of the film layer during the inkjet printing process.

[0238] The embodiments described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0239] Those skilled in the art can understand that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than those shown in the figures, or combine certain steps, or different steps.

[0240] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0241] Those of ordinary skill in the art can understand that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, and their appropriate combinations.

[0242] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above figures are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0243] It should be understood that in the present application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally means that the associated objects before and after are in an "or" relationship. "At least one (one) of the following" or a similar expression means any combination of these items, including any combination of single items (ones) or plural items (ones). For example, at least one (one) of a, b, or c may mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

[0244] In several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0245] The units described above as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0246] In addition, each functional unit in various embodiments of the present application can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0247] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes multiple instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in various embodiments of the present application. And the aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store programs.

[0248] The preferred embodiments of the embodiments of the present application have been described above with reference to the drawings, but this does not limit the scope of the rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall be within the scope of the rights of the embodiments of the present application.

Claims

1. A diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing, characterized in that: The method comprises: Acquire a first inkjet printing scheme to be evaluated, wherein the first inkjet printing scheme includes a plurality of printing parameters; Perform inkjet printing simulation according to the plurality of printing parameters to obtain a droplet state of the first inkjet printing scheme, wherein the droplet state is a final state of the droplet on the substrate; Determining the surface flatness of the droplet according to the state of the droplet; An evaluation result of the first inkjet printing scheme is determined according to the surface flatness of the droplets.

2. The method according to claim 1, characterized in that The plurality of printing parameters include at least two of substrate shape, inkjet printed droplet shape, droplet physical properties, initial concentration of active agent, active agent diffusion coefficient, substrate interface characteristics, and evaporation parameters; The step of performing inkjet printing simulation according to the plurality of printing parameters to obtain a droplet state of the first inkjet printing scheme includes: Building an inkjet printing model based on the plurality of printing parameters, the inkjet printing model being used to simulate a droplet formation process and a droplet spreading process on a substrate during inkjet printing; The plurality of printing parameters are subjected to inkjet printing simulation through the inkjet printing model to obtain the droplet state of the first inkjet printing solution.

3. The method according to claim 2, characterized in that The step of constructing an inkjet printing model based on the plurality of printing parameters comprises: Simulating the shape of the substrate and the shape of the inkjet-printed droplets by using a phase field function, and describing the spreading process of the droplets on the substrate by using a phase field method; According to the evaporation parameters, simulating the evaporation process of the droplet surface; According to the thickness of the droplet surface and the diffusion coefficient of the active agent, simulating the dissolution rate of the active agent in the droplet and the concentration distribution of the active agent on the droplet surface; According to the physical properties of the droplet, namely, the density of the droplet, the viscosity of the droplet, and the surface tension of the droplet, the mass conservation and momentum balance of the droplet during the printing process are simulated; Simulating the roughness of the substrate and the movement process of the contact line between the droplet and the substrate in the substrate interface characteristics according to the slip length; The inkjet printing model is obtained by adopting a diffusion domain method, simulating the substrate structure through an interface function, and expanding the calculation area to a regular geometric area.

4. The method according to claim 3, characterized in that Determining the surface flatness of the droplet according to the state of the droplet includes: Using the contour lines of the phase field function to represent the state of the liquid droplet, wherein the position where the contour lines of the phase field function are 0 represents the surface of the liquid droplet; Calculating a target fitting straight line according to the position points on the surface of the droplet, wherein the sum of the vertical distances between the target fitting straight line and the position points on the surface of each droplet is the smallest; The surface flatness of the droplet is determined according to the deviation between the surface of the droplet and the target fitting straight line.

5. The method according to claim 4, characterized in that Determining the surface flatness of the droplet according to the deviation between the surface of the droplet and the target fitting straight line includes: Respectively obtaining the distance from each position point on the surface of the droplet to the target fitting straight line; Perform square sum operation on the obtained distances to obtain the target square sum; The square root of the target sum of squares is taken as the error degree; The flatness is evaluated according to the error to obtain the flatness of the surface of the droplet.

6. The method according to claim 1, characterized in that After determining the evaluation result of the first inkjet printing scheme, the method further includes: Determining whether a score in the evaluation result of the first inkjet printing solution exceeds a preset threshold; If the score in the evaluation result of the first inkjet printing solution exceeds a preset threshold, outputting the evaluation result of the first inkjet printing solution; If the score in the evaluation result of the first inkjet printing scheme does not exceed the preset threshold, the printing parameters to be optimized in the first inkjet printing scheme and the optimization interval corresponding to each of the printing parameters to be optimized are determined, and the evaluation result of the first inkjet printing scheme, the printing parameters to be optimized and the optimization interval corresponding to each of the printing parameters to be optimized are output.

7. The method according to claim 6, characterized in that After determining the printing parameters to be optimized in the first inkjet printing scheme and the optimization interval corresponding to each of the printing parameters to be optimized if the score in the evaluation result of the first inkjet printing scheme does not exceed the preset threshold, and outputting the evaluation result of the first inkjet printing scheme, the printing parameters to be optimized, and the optimization interval corresponding to each of the printing parameters to be optimized, the method further includes: Using the first inkjet printing scheme as a current inkjet printing scheme, using the printing parameters to be optimized of the first inkjet printing scheme as target parameters, and using the optimization interval corresponding to the printing parameters to be optimized as the target interval; regenerating a plurality of temporary inkjet printing schemes according to target parameters of the current inkjet printing scheme and target intervals corresponding to the target parameters; Performing inkjet printing simulation on each of the temporary inkjet printing schemes to obtain an evaluation result corresponding to each of the temporary inkjet printing schemes; taking the temporary inkjet printing scheme corresponding to the highest-scoring evaluation result among the evaluation results corresponding to the plurality of temporary inkjet printing schemes as the target inkjet printing scheme; If the score in the evaluation result of the target inkjet printing scheme exceeds a preset threshold, outputting the evaluation result of the target inkjet printing scheme; If the score in the evaluation result of the target inkjet printing scheme does not exceed the preset threshold, determining the printing parameters to be optimized in the target inkjet printing scheme and the optimization interval corresponding to each of the printing parameters to be optimized; Taking the target inkjet printing scheme as the current inkjet printing scheme, taking the printing parameters to be optimized of the target inkjet printing scheme as the target parameters, and taking the optimization interval corresponding to the printing parameters to be optimized as the target interval, and executing the step of regenerating a plurality of temporary inkjet printing schemes according to the target parameters of the current inkjet printing scheme and the target interval corresponding to the target parameters; If the score in the evaluation result of the target inkjet printing scheme exceeds a preset threshold, the evaluation result of the target inkjet printing scheme is output.

8. A diffusion domain simulation device for suppressing the coffee ring effect in OLED inkjet printing, characterized in that: The device comprises: An acquisition module, for acquiring a first inkjet printing scheme to be evaluated, wherein the first inkjet printing scheme includes a plurality of printing parameters; A simulation module, performing inkjet printing simulation according to the plurality of printing parameters to obtain a droplet state of the first inkjet printing scheme, wherein the droplet state is a final state of the droplet on the substrate; A calculation module, which determines the surface flatness of the droplet according to the state of the droplet; An evaluation module determines an evaluation result of the first inkjet printing scheme according to the surface flatness of the droplets.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing as described in any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the diffusion domain simulation method for suppressing the coffee ring effect in OLED inkjet printing according to any one of claims 1 to 7 is implemented.

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