A method for inkjet printing large size panel film formation uniformity optimization

Abstract

The present application belongs to the technical field of inkjet printing and pressure reduction film forming, and particularly relates to a method for optimizing film forming consistency of a large-size panel for inkjet printing, which comprises the following steps: in the process of droplet evaporation and film forming, three groups of observation components are used to observe the film forming images of the center, edge and corner regions of the printing substrate in the cavity above the large-size pressure reduction evaporation cavity; the film forming images of each region are processed to extract the current droplet volume of each single pixel pit; the difference between the preset current reference volume and the current droplet volume of each single pixel pit is determined, and the target temperature of the corresponding region is determined in combination with the relationship formula based on temperature and evaporation speed; the temperature of the region is controlled by the temperature controller of the corresponding region based on the difference between the target temperature and the actual temperature; the above steps are repeated until the droplets on the printing substrate are completely formed or the process time is over. The present application can realize the consistency of pressure reduction evaporation film forming on line.

Description

Technical Field

[0001] This invention belongs to the technical field of inkjet printing decompression film formation, and more specifically, relates to a method for optimizing the film formation consistency of large-size panels for inkjet printing. Background Technology

[0002] Inkjet printing, as an additive manufacturing process, is considered a key component of emerging display technologies due to its high material utilization, simplified process flow, and suitability for large-size flexible production. Currently, many panel manufacturers have invested in the research and development of inkjet printing equipment and conducted a series of OLED printing production experiments. However, in the initial exploration phase of the process route, some problems still need to be addressed. For example, during the evaporation film formation process of large-size panels, the uneven evaporation rate of droplets in different regions due to differences in the suction gas field and vapor concentration leads to poor consistency in the final film morphology. Insufficient film consistency not only affects the display effect of large-size panels but also negatively impacts key performance indicators such as lifespan. Therefore, it is essential to monitor and actively adjust the evaporation process of large-size panels in the reduced-pressure evaporation system in real time to optimize the final film consistency.

[0003] Existing reduced-pressure evaporation systems address the aforementioned problems by adding a ring of solution around the perimeter to balance the evaporation rate in each region. However, most systems lack real-time monitoring capabilities for the evaporation process on large-size panels, failing to detect local anomalies during film formation and hindering rapid adjustment of process parameters to maintain film consistency. Furthermore, they exhibit poor adaptability to different materials or substrate sizes, resulting in insufficient process versatility and robustness. Therefore, it is necessary to optimize the design of reduced-pressure evaporation systems, improve their functional design, and propose a proactive, real-time monitoring and adjustment method for optimizing film formation consistency. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a method for optimizing the film formation consistency of large-size panels for inkjet printing. Its purpose is to solve the technical problem of poor film formation consistency in different areas in the existing vacuum evaporation film formation process due to the inability to detect abnormalities in the evaporation and curing process in real time.

[0005] To achieve the above objectives, according to one aspect of the present invention, a method for optimizing film formation consistency in large-size panels for inkjet printing is provided, comprising:

[0006] S1. During the droplet evaporation film formation process, three sets of observation components are used to observe the film formation images of the center, edge and corner regions of the printed substrate located in the large-size depressurized evaporation chamber. The film formation images of each region are processed to extract the current droplet volume of each individual pixel pit.

[0007] S2. Determine the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and based on the relationship between temperature and evaporation rate, combine the difference with the actual pressure collected in the cavity to determine the target temperature of the corresponding region; based on the difference between the determined target temperature of each region and the actual temperature of the corresponding region collected by the sensor, control the temperature of the region through the temperature controller of the corresponding region so that the overall evaporation rate of the droplets in each region is consistent.

[0008] S3. Repeat steps S1-S2 during the evaporation process until the droplets on the printed substrate are completely formed into a film or the process time ends.

[0009] Furthermore, in S1, the current droplet volume of a single pixel pit in each region is calculated as follows:

[0010]

[0011] In the formula, V is the current volume of a single droplet, R is the measured real-time contact radius of a single droplet, and θ is the measured real-time contact angle of a single droplet.

[0012] Furthermore, in S2, the current droplet volume of a single pixel pit in the central region is used as the preset current reference volume. Based on the relationship between temperature and evaporation rate, the target temperatures of the edge and corner regions are determined by the following formulas:

[0013]

[0014] In the formula, Δt represents the time interval for temperature adjustment, and V c V represents the current droplet volume of a single pixel pit in the central region. e V represents the current droplet volume of a single pixel pit in the edge region. m T represents the current droplet volume of a single pixel pit in the corner region; e T represents the substrate temperature of the edge region to be determined. m T represents the substrate temperature of the corner region to be determined. C Indicates the current substrate temperature in the middle region; P ∞,e P ∞,m P ∞，c These represent the air pressures in the edge, corner, and center regions, determined through actual measurements, respectively; M represents the molecular weight of the droplet, ρ represents the density of the droplet, R represents the ideal gas constant, and P represents the pressure of the droplet. v (T) represents the saturated vapor pressure of the droplet at temperature T; D represents the diffusion coefficient of the droplet; A represents the surface area of ​​the droplet.

[0015] Furthermore, in S2, if a specific target value is preset as the current reference volume, then based on the relationship between temperature and evaporation rate, the target temperatures of the central region, edge region, and corner region are determined by the following formulas:

[0016]

[0017] In the formula, V represents the current reference volume; V c V represents the current droplet volume of a single pixel pit in the central region. e V represents the current droplet volume of a single pixel pit in the edge region. m This represents the current droplet volume of a single pixel pit in the corner region; M represents the molecular weight of the droplet, ρ represents the density of the droplet, R represents the ideal gas constant, and P... v (T) represents the saturated vapor pressure of the droplet at temperature T; D represents the diffusion coefficient of the droplet; A represents the surface area of ​​the droplet; T e T represents the substrate temperature of the edge region to be determined. m T represents the substrate temperature of the corner region to be determined. C This indicates the current substrate temperature in the middle region; Δt represents the time interval for temperature adjustment; P ∞，e P ∞，m P ∞，c These represent the air pressure in the edge region, corner region, and middle region, respectively, as determined by actual measurements.

[0018] According to another aspect of the present invention, a large-size depressurized evaporation system for inkjet printing is provided, comprising: a large-size depressurized evaporation chamber, a pressure control component, three sets of observation components, a controller, and a temperature control component;

[0019] The large-size vacuum evaporation chamber serves as the film-forming space for a large-size panel. The pressure control component is used to temporarily pressurize and repressurize the large-size vacuum evaporation chamber under any vacuum level. The three sets of observation components are respectively located outside the large-size vacuum evaporation chamber and directly above the center, edge, and corner regions of the printed substrate inside the chamber. They are used to observe the film-forming images of the center, edge, and corner regions of the printed substrate inside the chamber through observation windows on the chamber during the droplet evaporation film-forming process. The temperature control component is used to collect the actual temperature of the substrate in each region.

[0020] The controller is used to execute the following steps in the large-size panel film formation consistency optimization method described above: process the film formation image of each region, extract the current droplet volume of a single pixel pit in each region, determine the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and determine the target temperature of the corresponding region based on the relationship between temperature and evaporation rate, combined with the difference and the actual pressure in the cavity; and determine the modulation temperature of the corresponding region based on the difference between the determined target temperature of each region and the actual temperature collected.

[0021] The temperature control component is also used to control the temperature of each region based on the modulated temperature, so that the overall evaporation rate of the droplets in each region is consistent.

[0022] Furthermore, the temperature control component includes three temperature controllers, corresponding temperature sensors, and water bath heating pipes; each temperature controller is used to regulate the substrate temperature of the corresponding area.

[0023] Furthermore, each set of observation components includes an observation camera, a coaxial light source, and a lens; these are used to continuously trigger the system via a controller, ensuring that the camera and light source work together to acquire real-time images of the film formation in the corresponding area.

[0024] In summary, compared with the prior art, the technical solutions conceived by this invention have the following main advantages:

[0025] 1. This invention proposes a method for optimizing film formation consistency in large-size panels using inkjet printing. It obtains droplet image information from the center, edges, and corners using a visual observation component, and then calculates the current droplet volume of a single pixel pit in each region. By comparing the volume differences between regions—that is, determining the difference between a preset current reference volume and the current droplet volume of a single pixel pit in each region—and based on the relationship between temperature and evaporation rate, determines the target temperature for the corresponding region using the above difference, adjusting the region temperature in the next time interval, the evaporation process of large-scale droplets can be synchronized, thereby achieving highly consistent film formation results. Therefore, this invention solves the technical problem of poor film formation consistency in different regions in existing vacuum evaporation film formation methods due to the inability to detect anomalies during the evaporation and curing process in real time.

[0026] 2. The present invention further proposes to select the current droplet volume of a single pixel pit in any region as the reference volume, and adjust the evaporation rate of the other two regions to make the droplet volume of the entire panel consistent. Since the evaporation rate of the central region is usually more reasonable and accurate, the current droplet volume of a single pixel pit in the central region is preferred as the reference to determine the control temperature of the edge and corner regions, thereby efficiently achieving film formation consistency.

[0027] 3. The present invention further proposes to preset a volume as a reference volume, which can more flexibly meet the actual generation needs. Attached Figure Description

[0028] Figure 1 This is a flowchart of a method for optimizing film formation consistency in large-size panels for inkjet printing, provided by an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of a large-size reduced-pressure evaporation system for inkjet printing provided in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the structure of the inkjet printing stage provided in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of a droplet volume observation and measurement method for inkjet printing provided in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the information flow of the consistency optimization method for inkjet printing provided in an embodiment of the present invention;

[0033] Figure 6 This is a control system composition diagram for inkjet printing provided in an embodiment of the present invention;

[0034] Figure 7 This is a flowchart of a film formation consistency optimization method for inkjet printing provided in an embodiment of the present invention.

[0035] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0036] 11 is the cavity; 12 is the observation window; 13 is the support platform; 21, 22, and 23 are three temperature controllers; 24, 25, and 26 are three water bath pipes; 27, 28, and 29 are three humidity sensors; 210, 211, and 212 are three temperature sensors; 31, 32, and 33 are three sets of observation components; 311 is the observation camera; 312 is the lens; 313 is the coaxial light source; 41 is the vacuum pump; 42 and 43 are two vacuum solenoid valves; 44 is the pressure gauge; 45 is the make-up gas source; and 51 is the controller. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention 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 merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0038] Example 1

[0039] A method for optimizing film formation consistency in large-size panels for inkjet printing, such as Figure 1 As shown, it includes:

[0040] S1. During the droplet evaporation film formation process, three sets of observation components are used to observe the film formation images of the center, edge and corner regions of the printed substrate located in the large-size depressurized evaporation chamber. The film formation images of each region are processed to extract the current droplet volume of each individual pixel pit.

[0041] S2. Determine the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and based on the relationship between temperature and evaporation rate, combine the difference with the actual pressure collected in the cavity to determine the target temperature of the corresponding region; based on the difference between the determined target temperature of each region and the actual temperature of the corresponding region collected by the sensor, control the temperature of the region through the temperature controller of the corresponding region so that the overall evaporation rate of the droplets in each region is consistent.

[0042] S3. Repeat steps S1-S2 during the evaporation process until the droplets on the printed substrate are completely formed into a film or the process time ends.

[0043] Based on the film formation images, real-time parameters such as droplet diameter, volume, and evaporation rate can be obtained through image processing algorithms and feature extraction techniques. Three temperature controllers can be used to independently control the temperature distribution in the center, edges, and corners of the substrate.

[0044] This embodiment proposes a film formation consistency optimization method based on a reduced-pressure evaporation system. It obtains droplet image information for each region using a visual observation component and then calculates the droplet volume for each region. By comparing the volume differences between regions and adjusting the region temperature in the next time interval based on the relationship between temperature and evaporation rate, the evaporation process of large-scale droplets can be synchronized, thereby achieving highly consistent film formation results.

[0045] As a preferred implementation, in S1, the current droplet volume of a single pixel pit in each region is calculated as follows:

[0046]

[0047] In the formula, V is the current volume of a single droplet, R is the measured real-time contact radius of a single droplet, and θ is the measured real-time contact angle of a single droplet.

[0048] Regarding the relationship between temperature and evaporation rate, the evaporation rate of droplets in each region... Represented as:

[0049]

[0050] In the formula, t is the evaporation time, D is the diffusion coefficient of the droplet, which is related to the specific type of droplet, M is the molecular weight of the droplet, ρ is the density of the droplet, R is the ideal gas constant, T is the droplet temperature, and P is the molecular weight of the droplet. v (T) is the saturated vapor pressure of the droplet at temperature T, C ∞ P is the vapor partial pressure in the cavity, and A is the surface area of ​​the droplet. v (T) Specifically: In the formula, L is the latent heat of vaporization of the droplet, and C is the integration constant, which is relevant to a specific uniform droplet. The vapor partial pressure C... ∞ Both temperature T and humidity T can be obtained by temperature and humidity sensors in different areas of the vacuum evaporation system.

[0051] During temperature adjustment, the real-time droplet volume V of individual pixel pits in the three regions is used as a reference. c V e and V m Determine the temperature T of each region in the next time interval. c T e and T m The droplet volume of any region can be selected as the reference volume, and the evaporation rates of the other two regions can be adjusted to make the droplet volume of the entire panel consistent. Preferably, the droplet volume of the central region is selected as the reference. By adjusting the temperature of the edges and corners of the large-size substrate, the real-time droplet volume of the three regions is made consistent.

[0052] Therefore, as a preferred implementation, in S2, the current droplet volume of a single pixel pit in the central region is used as a preset current reference volume. Based on the relationship between temperature and evaporation rate, the target temperatures of the edge and corner regions are determined by the following formulas:

[0053]

[0054] In the formula, Δt represents the time interval for temperature adjustment, and V c V represents the current droplet volume of a single pixel pit in the central region. e V represents the current droplet volume of a single pixel pit in the edge region. m T represents the current droplet volume of a single pixel pit in the corner region; e T represents the substrate temperature of the edge region to be determined. m T represents the substrate temperature of the corner region to be determined. C Indicates the current substrate temperature in the middle region; P ∞,e P ∞,m P ∞,cThese represent the air pressures in the edge, corner, and center regions, determined through actual measurements, respectively; M represents the molecular weight of the droplet, ρ represents the density of the droplet, R represents the ideal gas constant, and P represents the pressure of the droplet. v (T) represents the saturated vapor pressure of the droplet at temperature T; D represents the diffusion coefficient of the droplet; A represents the surface area of ​​the droplet.

[0055] As a preferred alternative implementation, in S2, a specific target value is preset as the current reference volume. Then, based on the relationship between temperature and evaporation rate, the target temperatures of the central region, edge region, and corner region are determined by the following formulas:

[0056]

[0057] In the formula, V represents the current reference volume; V c V represents the current droplet volume of a single pixel pit in the central region. e V represents the current droplet volume of a single pixel pit in the edge region. m This represents the current droplet volume of a single pixel pit in the corner region; M represents the molecular weight of the droplet, ρ represents the density of the droplet, R represents the ideal gas constant, and P... v (T) represents the saturated vapor pressure of the droplet at temperature T; D represents the diffusion coefficient of the droplet; A represents the surface area of ​​the droplet; T e T represents the substrate temperature of the edge region to be determined. m T represents the substrate temperature of the corner region to be determined. C This indicates the current substrate temperature in the middle region; Δt represents the time interval for temperature adjustment; P ∞,e P ∞，m P ∞，c These represent the air pressure in the edge region, corner region, and middle region, respectively, as determined by actual measurements.

[0058] Example 2

[0059] A large-size reduced-pressure evaporation system for inkjet printing includes: a large-size reduced-pressure evaporation chamber, a pressure control component, three sets of observation components, a controller, and a temperature control component.

[0060] The large-size vacuum evaporation chamber, serving as the film-forming space for large-size panels, includes a chamber and a stage, and is the main site for evaporation and film formation of the printed substrate. The pressure control component is used to apply temporary and reverse pressure to the large-size vacuum evaporation chamber at any vacuum level. Three sets of observation components are respectively located outside the large-size vacuum evaporation chamber and directly above the center, edge, and corner regions of the printed substrate within the chamber. These components are used to observe the film-forming images of the center, edge, and corner regions of the printed substrate within the chamber through observation windows on the chamber during the droplet evaporation process. The temperature control component is used to acquire the actual temperature of the substrate in each region.

[0061] The controller is used to execute the following steps in the large-size panel film formation consistency optimization method described above: process the film formation image of each region, extract the current droplet volume of a single pixel pit in each region, determine the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and determine the target temperature of the corresponding region based on the relationship between temperature and evaporation rate, combined with the above difference and the actual pressure in the cavity; and determine the modulation temperature of the corresponding region based on the difference between the determined target temperature of each region and the actual temperature collected.

[0062] The temperature control component is also used to control the temperature of each region based on the modulated temperature, so that the overall evaporation rate of droplets in each region is consistent.

[0063] Unlike existing vacuum evaporation systems, which lack information on the evaporation state and process of droplets within the drying chamber after the printed substrate is placed inside, resulting in uncontrollable film formation, this embodiment employs multiple visual observation systems to monitor the droplet evaporation state in different areas during the vacuum chamber drying process in real time.

[0064] The pressure control component may include a vacuum pump, evacuation piping, vacuum solenoid valve, make-up gas source, and pressure gauge, enabling the chamber to undergo temporary and backpressure operations at any vacuum level. In summary, the controller receives and processes real-time information acquired by the reduced-pressure evaporation system and sends control signals; the observation component is mounted on the top of the chamber, and an observation window is installed below it to ensure clear droplet images are acquired; the temperature control component is connected to the stage within the chamber and controls the temperature distribution on the stage.

[0065] As a preferred embodiment, the temperature control component includes three temperature controllers, corresponding temperature sensors, and water bath heating pipes; each temperature controller is used to regulate the substrate temperature of the corresponding area.

[0066] By installing temperature sensors within the reduced-pressure evaporation system, the droplet evaporation rate in each region can be calculated in real time. Furthermore, by implementing temperature zone control at the edges, corners, and center, the droplet evaporation rate in each region can be adjusted.

[0067] As a preferred embodiment, each set of observation components includes an observation camera, a coaxial light source, and a lens; it is used to continuously trigger via a controller to ensure that the camera and the light source work together to acquire film-forming images of the corresponding area in real time.

[0068] Based on the film formation image, the controller obtains real-time parameters such as droplet diameter, volume, and evaporation rate through image processing algorithms and feature extraction techniques. One set is installed at the center, edge, and corner of the printed substrate to monitor the evaporation status in different substrate areas.

[0069] Figure 2 This is a schematic diagram of a reduced-pressure evaporation system used for inkjet printing. The system mainly includes a large-size reduced-pressure evaporation chamber, pressure control components, observation components, temperature control components, and a controller. Figure 3 and Figure 4 These are schematic diagrams of the stage used for inkjet printing and the method for observing and measuring droplet volume. Each of these will be explained in detail below.

[0070] like Figure 2 As shown, the large-size vacuum evaporation chamber includes a chamber 11, an observation window 12, and a support stage 13. The chamber 11 is a closed space that creates a vacuum environment for the vacuum evaporation of ink droplets on the inkjet-printed substrate, resulting in a uniform film morphology. The observation window 12, mounted above the chamber, ensures that the observation camera can properly capture images of the droplet evaporation. The support stage 13 supports the printed substrate, providing support and heat transfer within the chamber.

[0071] The temperature control components include thermostats 21, 22, and 23, water bath pipes 24, 25, and 26, humidity sensors 27, 28, and 29, and temperature sensors 210, 211, and 212. The three thermostats control the temperature of the central, edge, and corner areas respectively, allowing adjustment of the temperature of the transmitted medium. The water bath pipes, serving as the medium carrier, are connected to pipe interfaces inside the support platform. The temperature and humidity sensors monitor the temperature and vapor pressure information of each area during droplet evaporation.

[0072] The observation unit includes three observation devices 31, 32, and 33, each consisting of an observation camera 311, a lens 312, and a coaxial light source 313. The observation unit is mounted above the observation window to collect real-time data on the droplet evaporation process in each area.

[0073] The pressure control components include a vacuum pump 41, vacuum solenoid valves 42 and 43, a pressure gauge 44, and a gas supply 45. The vacuum pump can reduce the pressure and create a vacuum in the chamber. The vacuum solenoid valves control the opening and closing of the evacuation line to achieve stable pressure reduction. The pressure gauge monitors the pressure inside the chamber in real time to prevent pressure overshoot or failure to reach the specified pressure. The gas supply replenishes the chamber with gas after the drying process to restore it to atmospheric pressure.

[0074] The controller 51 collects and processes information from various sensors, obtaining droplet images and environmental information from different areas during evaporation to determine whether temperature adjustment is necessary. Additionally, the controller sends various commands to the vacuum pump, solenoid valve, temperature controller, etc., to achieve pressure and temperature regulation.

[0075] like Figure 3 As shown, the temperature control unit can achieve zoned temperature control of the support platform. The water bath piping is divided into three lines, laid in the center, edge, and corner areas of the support platform respectively. This zoned piping allows for temperature adjustment when the evaporation rate of droplets differs in different areas.

[0076] like Figure 4 As shown, the observation component uses a camera 311 as a sensor to acquire image information. It acquires image information of the droplet through a lens 312 and a coaxial light source 313, and transmits it to the controller for processing to obtain the real-time radius and contact angle of the droplet.

[0077] like Figure 5 and Figure 6 The figures show the information flow diagram of the consistency optimization method and the control system composition diagram of this embodiment, respectively. Temperature sensors 210, 211, and 212 can obtain the real-time temperature of each region; humidity sensors 27, 28, and 29 can obtain the real-time vapor pressure of each region. The controller 51 collects the droplet environment information of each region and calculates the evaporation rate of that region.

[0078] After obtaining the real-time volume and evaporation rate of droplets in each region, and considering the possibility of inconsistent evaporation rates and processes in each region, the substrate temperature in each region is controlled based on a preset reference volume.

[0079] For example, such as Figure 7 A method for reducing pressure evaporation in inkjet printing is shown, comprising the following steps:

[0080] (1) Set the initial temperature of the stage 13, and heat the stage 13 through the water bath pipeline by each temperature controller 21, 22, 23;

[0081] (2) After the printed panel is transferred into the vacuum system, the pressure inside the cavity is pumped to a specified vacuum level by the pressure control component, so that the droplets on the printed panel evaporate into a film.

[0082] (3) Based on the acquisition of film-forming images, the controller 51 calculates the current droplet volume of a single pixel pit in different regions and calculates the droplet evaporation rate in each region;

[0083] (4) Calculate the adjusted stage temperature of each area, and send instructions from controller 51 to the corresponding temperature controllers 21, 22, 23 for adjustment;

[0084] (5) Repeat steps (3)-(4) until the film is completely formed or the process time ends;

[0085] (6) The controller 51 sends a command to the air supply 45 to replenish the air in the cavity and pressurize it to atmospheric pressure. The dried panel is then removed.

[0086] The relevant technical solutions are the same as in Embodiment 1, and will not be repeated here.

[0087] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for optimizing film formation consistency in large-size panels for inkjet printing, characterized in that, include: S1. During the droplet evaporation film formation process, three sets of observation components are used to observe the film formation images of the center, edge and corner regions of the printed substrate located in the large-size depressurized evaporation chamber. The film formation images of each region are processed to extract the current droplet volume of each individual pixel pit. S2. Determine the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and based on the relationship between temperature and evaporation rate, combine the difference with the actual pressure collected in the cavity to determine the target temperature of the corresponding region. Based on the difference between the target temperature of each region and the actual temperature of the corresponding region collected by the sensor, the temperature of the corresponding region is controlled by the temperature controller of the corresponding region, so that the overall evaporation rate of the droplets in each region is consistent. S3. Repeat steps S1-S2 during the evaporation process until the droplets on the printed substrate are completely filmed or the process time ends. In S2, the current droplet volume of a single pixel pit in the central region is used as the preset current reference volume. Based on the relationship between temperature and evaporation rate, the target temperatures of the edge and corner regions are determined by the following formulas: ； ； In the formula, Indicates the time interval for temperature adjustment. This represents the current droplet volume of a single pixel pit in the central region. This represents the current droplet volume of a single pixel pit in the edge region. This represents the current droplet volume of a single pixel pit in the corner region; This indicates the substrate temperature of the edge region to be determined. This indicates the substrate temperature of the corner region to be determined. This indicates the current substrate temperature in the middle region; , , These represent the air pressure in the edge region, corner region, and middle region, respectively, as determined by actual measurements. Indicates the molecular weight of the droplet. This represents the density of the droplet. Represents the ideal gas constant. Indicates the temperature of the droplet The saturated vapor pressure below; This represents the diffusion coefficient of the droplet; Surface area of ​​the liquid droplet; Alternatively, in S2, if a target value is preset as the current reference volume, then based on the relationship between temperature and evaporation rate, the target temperatures of the central region, edge region, and corner region are determined by the following formulas: ； ； ； In the formula, Indicates the current reference volume; This represents the current droplet volume of a single pixel pit in the central region. This represents the current droplet volume of a single pixel pit in the edge region. This represents the current droplet volume of a single pixel pit in the corner region; Indicates the molecular weight of the droplet. This represents the density of the droplet. Represents the ideal gas constant. Indicates the temperature of the droplet The saturated vapor pressure below; This represents the diffusion coefficient of the droplet; Surface area of ​​the liquid droplet; This indicates the substrate temperature of the edge region to be determined. This indicates the substrate temperature of the corner region to be determined. This indicates the current substrate temperature in the middle region; Indicates the time interval for temperature adjustment; , , These represent the air pressure in the edge region, corner region, and middle region, respectively, as determined by actual measurements.

2. The method for optimizing film uniformity in large-size panels as described in claim 1, characterized in that, In S1, the current droplet volume of a single pixel pit in each region is calculated as follows: In the formula, It is the current volume of a single droplet. It is the measured real-time contact radius of a single droplet. It is the real-time contact angle of a single droplet as measured.

3. A large-size reduced-pressure evaporation system for inkjet printing, characterized in that, include: Large-size depressurized evaporation chamber, pressure control components, three sets of observation components, controller, and temperature control components; The large-size vacuum evaporation chamber serves as the film-forming space for a large-size panel. The pressure control component is used to temporarily pressurize and repressurize the large-size vacuum evaporation chamber under any vacuum level. The three sets of observation components are respectively located outside the large-size vacuum evaporation chamber and directly above the center, edge, and corner regions of the printed substrate inside the chamber. They are used to observe the film-forming images of the center, edge, and corner regions of the printed substrate inside the chamber through observation windows on the chamber during the droplet evaporation film-forming process. The temperature control component is used to collect the actual temperature of the substrate in each region. The controller is used to execute the following steps in the large-size panel film formation consistency optimization method as described in claim 1 or 2: processing the film formation image of each region, extracting the current droplet volume of a single pixel pit in each region, determining the difference between the preset current reference volume and the current droplet volume of a single pixel pit in each region, and determining the target temperature of the corresponding region based on the relationship between temperature and evaporation rate, combined with the difference and the actual pressure in the cavity; and determining the modulation temperature of the corresponding region based on the difference between the determined target temperature of each region and the collected actual temperature. The temperature control component is also used to control the temperature of each region based on the modulated temperature, so that the overall evaporation rate of the droplets in each region is consistent.

4. The large-size reduced-pressure evaporation system as described in claim 3, characterized in that, The temperature control component includes three temperature controllers, corresponding temperature sensors, and water bath heating pipes; each temperature controller is used to regulate the substrate temperature of its corresponding area.

5. The large-size reduced-pressure evaporation system as described in claim 3, characterized in that, Each set of observation components includes an observation camera, a coaxial light source, and a lens; it is used to continuously trigger via a controller to ensure that the camera and light source work together to acquire film-forming images of the corresponding area in real time.

Images