CN-121973557-A - Method for regulating and controlling flow field of vacuum drying cavity for ink-jet printing

CN121973557ACN 121973557 ACN121973557 ACN 121973557ACN-121973557-A

Abstract

The invention belongs to the technical field related to ink-jet printing, in particular to a flow field regulating and controlling method for a vacuum drying cavity for ink-jet printing, which comprises the following steps of uniformly configuring a plurality of independently controlled auxiliary air exhaust pipelines around the vacuum drying cavity; and if the current flow field uniformity coefficient does not meet the preset requirement, adopting a pre-trained agent prediction model, optimizing key parameter combination values according to a multi-target rolling optimization objective function, wherein the key parameters are various parameters which are determined in advance through feature importance analysis and influence film forming uniformity, including the flow of each auxiliary air extraction pipeline and related parameters of component layout in the cavity, and the multi-target rolling optimization objective function is the sum of the minimum uniformity lifting amplitude, the adjustment amplitude of each parameter and the adjustment frequency of each parameter. The invention can solve the problem of poor film drying consistency caused by uneven flow field distribution in the existing vacuum drying system.

Inventors

CHEN JIANKUI
LI ZHENXIAN
WU WENXIANG
CHEN YUJIANG

Assignees

华中科技大学

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (8)

1. A method for regulating and controlling a flow field of a vacuum drying cavity for ink-jet printing, which is characterized by comprising the following steps: a plurality of independently controlled auxiliary air exhaust pipelines are uniformly arranged around the vacuum drying cavity; Collecting cavity flow field data in real time, calculating the current flow field uniformity coefficient of the cavity, judging whether the current flow field uniformity coefficient meets the preset requirement, if so, keeping the combination value of the key parameters unchanged, if not, adopting a pre-trained agent prediction model, optimizing the target function according to multi-target rolling, optimizing the combination value of the key parameters, realizing regulation and control through control hardware, and finally realizing flow field regulation and control; The method comprises the steps of determining a key parameter of a cavity, wherein the key parameter is a plurality of parameters which are determined in advance through characteristic importance analysis and affect film forming uniformity, the parameters comprise flow of each auxiliary air exhaust pipeline and related parameters of component layout in the cavity, a multi-target rolling optimization objective function is the sum of a minimum uniformity liftable amplitude, a parameter adjustment amplitude and a parameter adjustment frequency, and in a preset time period, the parameters of an agent prediction model are updated on line based on cavity flow field data acquired in real time and corresponding cavity current flow field uniformity coefficients obtained through calculation.
2. The method for regulating and controlling the flow field of the vacuum drying cavity according to claim 1, wherein the key parameters are determined in the following manner: Sampling in the space of various parameters to establish a sample data set, wherein each sample data set comprises parameter combination values and flow field uniformity coefficients corresponding to the parameter combination values, the parameters comprise the flow rate Q i of each auxiliary air extraction pipeline, the distance H between a carrier and a condensing plate, the vertical distance H between the rectifying plate and an air extraction opening of a main air extraction pipeline, the temperature T s of the carrier and the temperature T c of the condensing plate, and the flow field uniformity coefficients are obtained by the steps of After the second ink-jet printing vacuum drying system is stabilized, measuring flow velocity of n points in a preset plane above the carrier by adopting a distributed flow velocity sensor, and calculating a flow field uniformity coefficient of the preset plane : In the formula, The value range is 0,1, Indicating the flow rate at the i-th measurement point, Representing a weighted average flow rate, , Representing the spatial weight coefficient at the ith sample point, and determining the coefficient according to the distance between the point and the key functional area; based on the sample dataset, key parameters are determined by feature importance analysis.
3. The method for regulating and controlling the flow field of the vacuum drying cavity according to claim 2, wherein the characteristic importance analysis method comprises the following steps: based on the sample data set, a random forest regression algorithm is adopted to score the feature importance of each parameter, wherein each tree adopts a self-help sampling method during training, and the maximum feature split number is set as And m is the number of parameter types, calculating the average radix importance score of each parameter in all decision trees, uniformly normalizing the scores of the parameters to the [0, 1] interval, forming a feature importance sorting list, and reserving the parameters with importance scores larger than a threshold value to finish the determination of key parameters.
4. The method for regulating and controlling the flow field of the vacuum drying cavity according to claim 2, wherein the proxy prediction model is constructed in the following manner: constructing a sample set, wherein each sample comprises key parameter combination values and flow field uniformity coefficients of corresponding preset planes ; A training sample set is adopted to construct a polynomial chaotic expansion model, which is expressed as follows: In which, in the process, In order to take the key parameter combination value X as the multidimensional Hermite basic function of the independent variable, The flow field uniformity coefficient of the preset plane under the value of X, Representing the order of the multidimensional Hermite basis function, For the coefficient to be determined through training, carrying sample data into a model formula, and carrying out calculation and solving by adopting a least square method or a projection method; Sampling test sample set not participating in training, and calculating model predicted value And true value The determination coefficient R2 and the average absolute error MAE between the model prediction accuracy are evaluated by adjusting the order And increasing the number of training samples, and improving the model precision.
5. The method for regulating and controlling the flow field of a vacuum drying cavity according to claim 1, wherein the multi-objective rolling optimization objective function is as follows: In the formula, In order to improve the term of uniformity, As the weight coefficient of the light-emitting diode, To take time from adjusting parameters The time from the start to the stabilization of the cavity flow field is taken as a value according to the specific structure of the system; is predicted by a proxy prediction model ) Presetting a planar flow field uniformity coefficient in the cavity at any time; For controlling the amplitude punishment item, the method is used for punishing the sum of the value adjustment amplitude of each key parameter, limiting the adjustment amplitude of each execution structure, For the adjustment amplitude of the j-th key parameter, Punishment weights are used for adjusting the amplitude of the jth key parameter, and the adjusting amplitude of each structure is limited; for the control frequency punishment item, the utility model is used for punishing the frequency of the value control of each key parameter, Is the regulation frequency of the jth key parameter, Punishment weights are applied to the regulation frequency of the jth key parameter. The constraint conditions of the multi-target rolling optimization objective function are as follows: In the formula, , Respectively regulating the minimum value and the maximum value of the jth key parameter; At the moment of the j-th key parameter ) Taking the value of the lower part; and the minimum flow field uniformity coefficient required for system design is the preset requirement.
6. The method for regulating and controlling the flow field of a vacuum drying cavity according to claim 1, wherein the parameters of the proxy model are updated on line by adopting a recursive least square method.
7. A vacuum drying system for ink-jet printing is characterized by comprising a vacuum cavity, a carrying platform, a condensing plate, a rectifying plate, a multi-sensor array and a control module; The vacuum cavity is internally configured into a high vacuum environment, a main air exhaust pipeline is arranged at the upper part of the cavity, N independently controlled air exhaust pipelines are uniformly distributed around the cavity, each pipeline is externally connected with a vacuum pump, a heating runner is arranged in a carrier and used for placing a substrate and maintaining the temperature of the substrate, a condensing plate is arranged above the carrier and is used for capturing steam and regulating and controlling the temperature gradient in the vertical direction of a space by vertically moving a lifting device, a rectifying plate is arranged at the inlet of the main air exhaust pipeline and used for changing the flow direction of fluid pumped by the main air exhaust pipeline and changing the flow field distribution of the fluid pumped by the main air exhaust pipeline, and a multi-sensor array is used for monitoring the flow field distribution in a preset plane above the carrier in real time; The control module is used for adjusting hardware corresponding to each key parameter by adopting the flow field adjusting and controlling method of the vacuum drying cavity according to any one of claims 1 to 6.
8. A computer readable storage medium, characterized in that the computer readable storage medium comprises a stored computer program, wherein the computer program, when run by a processor, controls a device in which the storage medium is located to perform the algorithm steps of the method according to any one of claims 1to 6.

Description

Method for regulating and controlling flow field of vacuum drying cavity for ink-jet printing Technical Field The invention belongs to the technical field related to ink-jet printing, and particularly relates to a flow field regulating and controlling method for a vacuum drying cavity for ink-jet printing. Background Inkjet printing is becoming a key technology in the new display field. Compared with the traditional vacuum evaporation process, the ink-jet printing technology gets rid of the limitation of the mask plate, so that the ink-jet printing technology has more advantages in the manufacture of large-size display equipment. In addition, inkjet printing is an additive manufacturing process, and its simple manufacturing process and efficient material utilization make it have broad prospects in commercial development. At present, various manufacturers at home and abroad have explored and developed ink jet printing equipment, and researchers propose a vacuum drying technology aiming at the problems of how to accelerate droplet evaporation, inhibit coffee rings in the droplet evaporation process and improve uniformity of large-area drying film, namely, putting a printed display panel in a vacuum environment for evaporation drying. External environmental factors influencing the uniformity of the film formation mainly comprise temperature, pressure, humidity, external gas flow rate and the like. However, in the existing ink-jet printing vacuum drying system, most of the methods only adopt temperature and pressure control, and large-area liquid drops are affected by an external uneven flow field during evaporation, so that the final film forming uniformity is poor, and the quality of a display device is affected. Therefore, the structure of the vacuum cavity needs to be optimized, the functional design of the vacuum drying system is perfected, and a flow field optimizing method of the vacuum drying system is provided. Disclosure of Invention Aiming at the defects or improvement demands of the prior art, the invention provides a flow field regulating and controlling method of a vacuum drying cavity for ink-jet printing, which aims to solve the problem of poor film drying consistency caused by uneven flow field distribution in the existing vacuum drying system. To achieve the above object, according to one aspect of the present invention, there is provided a vacuum drying chamber flow field regulating method for inkjet printing, comprising: a plurality of independently controlled auxiliary air exhaust pipelines are uniformly arranged around the vacuum drying cavity; Collecting cavity flow field data in real time, calculating the current flow field uniformity coefficient of the cavity, judging whether the current flow field uniformity coefficient meets the preset requirement, if so, keeping the combination value of the key parameters unchanged, if not, adopting a pre-trained agent prediction model, optimizing the target function according to multi-target rolling, optimizing the combination value of the key parameters, realizing regulation and control through control hardware, and finally realizing flow field regulation and control; The method comprises the steps of determining a key parameter of a cavity, wherein the key parameter is a plurality of parameters which are determined in advance through characteristic importance analysis and affect film forming uniformity, the parameters comprise flow of each auxiliary air exhaust pipeline and related parameters of component layout in the cavity, a multi-target rolling optimization objective function is the sum of a minimum uniformity liftable amplitude, a parameter adjustment amplitude and a parameter adjustment frequency, and in a preset time period, the parameters of an agent prediction model are updated on line based on cavity flow field data acquired in real time and corresponding cavity current flow field uniformity coefficients obtained through calculation. Further, the key parameters are determined in the following ways: Sampling in the space of various parameters to establish a sample data set, wherein each sample data set comprises parameter combination values and flow field uniformity coefficients corresponding to the parameter combination values, the parameters comprise the flow rate Q i of each auxiliary air extraction pipeline, the distance H between a carrier and a condensing plate, the vertical distance H between the rectifying plate and an air extraction opening of a main air extraction pipeline, the temperature T s of the carrier and the temperature T c of the condensing plate, and the flow field uniformity coefficients are obtained by the steps of After the second ink-jet printing vacuum drying system is stabilized, measuring flow velocity of n points in a preset plane above the carrier by adopting a distributed flow velocity sensor, and calculating a flow field uniformity coefficient of the preset plane: In the formula,The value range is 0,1,Indic