CN112078247A - Micron-order inkjet printing calculation and simulation method - Google Patents

Abstract

The invention provides a calculation and simulation method for micron-scale inkjet printing, which utilizes physical laws followed in a printing process to simulate the printing process and a micro-nano structure state under different experimental parameters. The method comprises the specific steps of ink ejection state simulation, ink drop spreading state simulation on a substrate and micro-nano structure printing line width and morphology simulation. According to the method, the spray printing state and the specific condition of the printing micro-nano structure are calculated and simulated in advance by setting different parameters in the ink-jet printing micro-nano structure, so that the optimal range of the parameters in the printing preparation process is quickly and accurately positioned, the optimal spray printing effect can be obtained in the fastest time by combining with the actual ink-jet printing process, the times of printing trial and error are reduced, the process cost is reduced, and the method has higher practical application value in the technical field of printing electronics.

Description

Micron-order inkjet printing calculation and simulation method

Technical Field

The invention relates to a calculation and simulation method for micron-scale inkjet printing, and belongs to the technical field of printing electronics.

Background

With the rapid development of organic electronics and printed electronics, the preparation of flexible, large-area, light, thin and low-cost electronic products by using a printing process becomes a hot spot of current research. Compared with the traditional silicon-based microelectronic product, the printing process endows the electronic product with brand-new product form and design concept. Among various printing technologies, the inkjet printing technology becomes a hot process for researching printing and preparing flexible electronics due to the characteristics of no contact, no mask, large-area preparation, controllable thickness, convenience in integration and the like, wherein the piezoelectric inkjet printing technology becomes a current mainstream technology due to the characteristics of stable inkjet, higher precision, simplicity and convenience in operation, lower price and the like.

However, the piezoelectric ink-jet printing of the patterned micro-nano structure is a fine operation process, and the resolution and the surface morphology of the micro-nano structure are greatly affected by slight changes of experimental conditions, so that two problems mainly face to the realization of high-quality micro-nano structure printing: the ink formula process is complicated. The ink is driven by voltage to be sprayed out from a nozzle with a micrometer caliber and form stable and uniform ink drops, and the requirements on the performance parameters of the ink are extremely strict. Most of ink can not be directly sprayed and printed in the experiment process due to the narrow ink performance window, and the stable spraying and printing effect can be realized only through repeated adjustment and experiments, so that the time cost, the labor cost and the material cost of the experiment are greatly increased, and the working efficiency is reduced; ② the equipment regulation process is complex. The parameters of the ink jet printing apparatus are various, such as the caliber and temperature of the nozzle, the driving waveform and voltage, the flying speed, the distance between printing points, the temperature of the substrate, etc. The printing process involves a number of microscopic regulatory processes including ink drop ejection, ink drop flight, ink drop impact with the substrate, ink drop flow and reconstruction on the substrate, etc. Each process is in turn influenced by a number of experimental parameters, such as impact of the ink drop on the substrate, substrate surface tension, ink viscosity and density. The control of each microscopic process directly affects the quality of the printed structure.

In summary, the ink configuration, parameter control and tracing of problem sources in piezoelectric inkjet printing are tedious, complex and difficult, have a strong dependence on operation experience, and result in a long and hard experimental early stage research process. Therefore, qualitative and quantitative changes of printing related process parameters under different experimental conditions are calculated and simulated according to the physical rules followed in the printing process, and corresponding printing states and changes of the printing micro-nano structure are further analyzed and simulated, so that the method is particularly important and necessary for improving the efficiency of the ink-jet printing micro-nano structure process and reducing the time cost and the economic cost of experimental trial and error.

Disclosure of Invention

The technical problem is as follows: the invention provides a micron-scale inkjet printing calculation and simulation method, which solves the technical problems of complex configuration and parameter regulation and control and strong operation experience dependence of the current micro-nano structure inkjet printing ink. Through the analysis and simulation of the printing state and the printing structure, the parameter adjusting efficiency of the micro-nano structure ink-jet printing is greatly improved, and the time cost and the economic cost of the experimental trial and error are reduced.

The technical scheme is as follows: the invention provides a micron-scale inkjet printing calculation and simulation method, which is characterized by comprising the following steps of: the method comprises the following steps:

1) simulating an ink ejection state;

2) simulating the spreading state of ink drops on a substrate;

3) and simulating the line width and the morphology of the printing micro-nano structure.

The method for calculating and simulating the micron-scale inkjet printing is characterized in that a dimensionless constant Z ═ gamma pa is adopted for simulating the ink ejecting state^1/2The/eta fuses the influence of the rho, eta, gamma and a on the ink ejection state, and performs software design and simulation of the ink ejection state on the basis of the theory, thereby realizing simulation and guidance on ink configuration, greatly improving the ink allocation efficiency and indicating the specific direction of ink performance improvement. Where ρ, η, and γ are the density, viscosity, and surface tension of the printing ink, respectively, and a is the diameter of the nozzle.

The method for calculating and simulating the micron-scale inkjet printing is characterized in that the simulation of the spreading state of the ink drop on the substrate adopts the Fowkes theory to carry out software design and the simulation of the spreading state of the ink drop, namely the surface tension of the substrate, the surface tension of the liquid and the contact between the substrate and the liquidThe relationship of the angle is 1+ cos θ ═ 2(γ)_l ^dγ_s ^d)^1/2+2(γ_l ^pγ_sp)^1/2]/γ_lWherein γ is_l ^d、γ_l ^pPolar and non-polar forces of the droplets, gamma_s ^d、γ_s ^pIs the polar and non-polar forces of the substrate surface, and theta is the contact angle between the two.

The micron-order inkjet printing calculation and simulation method is characterized in that the printing micro-nano structure line width and morphology simulation is based on an energy diffusion theory and a geometric principle to carry out software design and micro-nano structure morphology simulation, namely, the method follows a relational expression delta x-R₁＝y-(0.888/y)^1/2，y＝Δx/R₀And

where Δ x is the dot spacing, R₀Radius for spreading of ink droplet, R₁And R is the flying radius of the ink drop, and theta is the contact angle between the ink drop and the substrate.

Has the advantages that: the micron-scale inkjet printing calculation and simulation method can calculate and simulate relevant parameters of inkjet printing and specific conditions of printed line segments in advance by adjusting different parameters in the inkjet printing micro-nano structure, so that the parameter selection range in the printing preparation process is narrowed, the times of printing trial and error are reduced, the process cost is reduced, the optimal parameter ranges of ink, a substrate, inkjet printing conditions and the like of the inkjet printing micro-nano structure are simply, conveniently and quickly obtained, the optimal inkjet printing effect is obtained in the fastest time by combining with the actual inkjet printing process, and the rapid development of the process of printing electronics, especially the inkjet printing flexible electronic device is realized.

Drawings

FIG. 1 is an overall structure of the present invention

Detailed Description

The method utilizes the physical law followed in the printing process to establish the corresponding relation between the ink-jet state, the ink drop spreading state, the micro-nano structure appearance and the physical quantity in the printing process, and carries out simulation on the printing process and the micro-nano structure state under different experimental parameters.

Example 1

Printing was performed using ink 1, ink 2, ink 3, and ink 4, respectively, and simulation of the ink ejection state was performed before printing. The pre-judgment of the ink ejection state is obtained by measuring the physical parameters of the ink such as density, viscosity, surface tension, boiling point and the like. Ink 1 Density 0.86g/cm³The viscosity is 0.75CP, the surface tension is 30mN/m, the boiling point is 140 ℃, and xylene is easy to splash, skew or trailing in the ink drop jet printing process; ink 2 Density 0.95g/cm³The viscosity is 2.02CP, the surface tension is 34.5mN/m, the boiling point is 155 ℃, and the cyclohexanone is adopted, can be normally sprayed and printed, and can be smeared in even and odd bands; ink 3 Density 0.79g/cm³The ink has the viscosity of 1.18CP, the surface tension of 22.3mN/m, the boiling point of 78 ℃, is ethanol, and is easy to splash, volatilize or tailing in the ink drop jet printing process; ink 4 Density 0.95g/cm³The ink has the viscosity of 2.7CP, the surface tension of 34.8mN/m and the boiling point of 240 ℃, is phenylcyclohexane, and is easy to block in the ink drop jet printing process. And further giving out an ink blending direction according to the ink parameters and the estimated spray printing state: the density, boiling point and tension of the ink 1 are in the range of jettable, which results in an undesirable jet-printed state due to too low viscosity; the parameters of ink 2 are ideal; the density and the tension of the ink 3 are in a jet printing range, and the ink is volatilized in the jet printing process due to the excessively low boiling point, so that the ink jet state is unstable, and the low boiling point solvent is recommended to be replaced; the ink 4 density, boiling point and tension are in the jettable range because the viscosity is too high to easily clog.

Example 2

And (3) spraying and printing the ink 5 on the substrate 1, and simulating the spreading state of the ink 5 on the substrate and the appearance of the printing micro-nano structure in advance, thereby guiding the regulation and control of physical parameters in the spraying and printing process. Measuring the nonpolar force in the surface tension of the ink 5 to be 34mN/m and the polar force to be 20mN/m, measuring the nonpolar force in the surface tension of the substrate 1 to be 45.1mN/m and the polar force to be 0.933mN/m, measuring the volume of the jet printing ink drop to be 10PL, simulating the contact angle of the ink drop and the substrate to be 67.1 degrees and the spreading radius of the ink drop 5 on the surface of the substrate 1 to be 25.1 mu m according to the corresponding relation between the spreading state of the ink drop and physical parameters. When the printing dot spacing is set to be 5 mu m, the predicted printing line width is 105.7 mu m, coin stacking lines are formed on the surface of the micro-nano structure, and the printing dot spacing is recommended to be further increased.

Example 3

And (3) spraying and printing the ink 6 on the substrate 1, and simulating the spreading state of the ink 6 on the substrate and the appearance of the printing micro-nano structure in advance, thereby guiding the regulation and control of physical parameters in the spraying and printing process. Measuring the nonpolar force in the surface tension of the ink 6 to be 10mN/m and the polar force to be 30mN/m, measuring the nonpolar force in the surface tension of the substrate 1 to be 45.1mN/m and the polar force to be 0.933mN/m, measuring the volume of the jet printing ink drop to be 10PL, simulating the contact angle of the ink drop and the substrate to be 70.9 degrees and the spreading radius of the ink drop 6 on the surface of the substrate 1 to be 23.9 mu m according to the corresponding relation between the spreading state of the ink drop and physical parameters. When the printing dot pitch is set to 25 μm, the predicted printing line width is 44.1 μm, the ink droplets will be merged with each other after landing on the substrate, and the dot pitch is set reasonably.

Example 4

And (3) spraying and printing the ink 6 on the substrate 2, and simulating the spreading state of the ink 6 on the substrate and the appearance of the printing micro-nano structure in advance, thereby guiding the regulation and control of physical parameters in the spraying and printing process. Measuring the nonpolar force in the surface tension of the ink 6 to be 10mN/m and the polar force to be 30mN/m, measuring the nonpolar force in the surface tension of the substrate 2 to be 45.2mN/m and the polar force to be 5.91mN/m, measuring the volume of the jet printing ink drop to be 10PL, simulating the contact angle of the ink drop and the substrate to be 43.2 degrees according to the corresponding relation between the spreading state of the ink drop and the physical parameters, and measuring the spreading radius of the ink drop 6 on the surface of the substrate 2 to be 33.8 mu m. When the printing dot spacing is set to be 60 micrometers, the printing line width is predicted to be 47.9 micrometers, segment lines are easy to appear on the micro-nano structure, and the dot spacing is recommended to be reduced appropriately.

Claims (4)

1. A micrometer-scale ink-jet printing calculation and simulation method is characterized by comprising the following steps: the method comprises the following steps:

1) simulating an ink ejection state;

2) simulating the spreading state of ink drops on a substrate;

3) and simulating the line width and the morphology of the printing micro-nano structure.

2. According to the powerThe method for calculating and simulating micron-scale inkjet printing of claim 1, wherein the simulation of the ink ejection state uses a dimensionless constant Z ═ γ pa^1/2The method is characterized in that the method comprises the following steps of fusing influence of rho, eta, gamma and a parameters on the ink ejection state by the eta, and carrying out software design and simulation of the ink ejection state on the basis of the fusion parameters by taking the influence as a theoretical basis to realize simulation and guidance on ink configuration, greatly improving the ink blending efficiency and indicating the specific direction of ink performance improvement, wherein rho, eta and gamma are the density, viscosity and surface tension of printing ink respectively, and a is the diameter of a nozzle.

3. The method of calculating and simulating micrometer-scale inkjet printing as claimed in claim 1, wherein the simulation of the spreading state of the ink droplets on the substrate is performed by software design using Fowkes theory and simulation of the spreading state of the ink droplets, i.e., the relationship between the surface tension of the substrate and the surface tension of the liquid and the contact angle therebetween is 1+ cos θ ═ 2(γ θ)_l ^dγ_s ^d)^1/2+2(γ_l ^pγ_s ^p)^1/2]/γ_lWherein γ is_l ^d、γ_l ^pPolar and non-polar forces of the droplets, gamma_s ^d、γ_s ^pIs the polar and non-polar forces of the substrate surface, and theta is the contact angle between the two.

4. The method of calculating and simulating micron-scale inkjet printing according to claim 1, wherein the simulation of the line width and the morphology of the printed micro-nano structure is based on an energy diffusion theory and a geometric principle to perform software design and micro-nano structure morphology simulation, namely, the method follows a relational expression Δ x-R₁＝y-(0.888/y)^1/2，y＝Δx/R₀And

where Δ x is the dot spacing, R₀Radius for spreading of ink droplet, R₁And R is the flying radius of the ink drop, and theta is the contact angle between the ink drop and the substrate.

Images