Vacuum drying device and vacuum drying method for inkjet printing substrate

Abstract

The invention relates to the field of inkjet printing, and discloses a vacuum drying device for inkjet printing substrates and a vacuum drying method; the vacuum drying device for inkjet printing substrates comprises: a frame, a box, a first vacuum pump, a vacuuming pipeline system, a second vacuum pump, a bearing platform, a lifting module, a heating plate and a condensing plate; the box is arranged on the frame, and has a vacuum cavity inside; the first vacuum pump and the vacuuming pipeline system preliminarily evacuate the vacuum cavity; the bearing platform carries materials to be dried, and the lifting module drives the bearing platform to rise and fall; the heating plate is arranged on the bearing platform and is used for heating the materials; the condensing plate is located above the bearing platform and is used for condensing volatilized solvents; the second vacuum pump performs extreme vacuuming on the vacuum cavity to completely remove condensed solvent impurities; the invention optimizes the drying and film-forming process of an OLED substrate by precisely controlling the vacuum environment and flexibly adjusting the distance between the heating plate and the condensing plate, thereby completely removing solvent impurities, and making the film formation more uniform.

Description

Technical Field

[0001] The invention relates to the field of inkjet printing, and in particular to a vacuum drying device and a vacuum drying method for an inkjet printing substrate. Background Art

[0002] When manufacturing existing OLED displays, a wet process is usually used, that is, the material is made into ink or slurry for coating. In the wet process, a certain amount of solvent needs to be added to make the material into ink or slurry. In order to remove the solvent introduced in the wet process, a vacuum drying method is usually used. When the material is placed under vacuum negative pressure conditions, the boiling point of the solvent will decrease as the vacuum degree increases. Therefore, by reducing the pressure, the solvent can be volatilized and dried at a lower temperature. At the same time, the material will also be cured into a film due to heating. Finally, the product is cooled to form a product.

[0003] However, the existing vacuum drying process has certain defects. The main one is that when the vacuum is not fully drawn, the evaporated solvent may reversely condense and redeposit on the OLED display, resulting in poor uniformity of the material film. Summary of the invention

[0004] The present invention aims to improve at least one technical problem in the background technology.

[0005] A first aspect of the present invention provides an inkjet printing substrate vacuum drying device, comprising:

[0006] frame;

[0007] A box body is arranged on the frame, and a vacuum cavity is provided inside the box body;

[0008] A first vacuum pump is arranged outside the vacuum chamber, and the first vacuum pump is used to initially evacuate the vacuum chamber;

[0009] A vacuum pipe system, one end of which is connected to the first vacuum pump, and the other end of which is connected to the bottom of the vacuum chamber;

[0010] A second vacuum pump is arranged outside the vacuum chamber, and the second vacuum pump is used to evacuate the vacuum chamber to the extreme vacuum;

[0011] A carrying platform is arranged in the vacuum chamber; the carrying platform is used to carry the material to be dried;

[0012] A lifting module, arranged on the box body, and used for driving the carrying platform to lift;

[0013] A heating plate, arranged on the carrying platform, and used for heating the material on the carrying platform;

[0014] A condensation plate is arranged in the vacuum chamber and located above the carrying platform, and the condensation plate is used for condensing the volatilized solvent.

[0015] The beneficial effects of the embodiments of the first aspect of the present invention are as follows: during vacuum drying operation, the first vacuum pump cooperates with the vacuum evacuation pipeline system to achieve efficient and precise control of the air pressure in the vacuum chamber, thereby providing an ideal pressure environment for the drying and film-forming process of the OLED substrate; through the precise control of the lifting module, the distance between the heating plate and the condensation plate can be flexibly adjusted, thereby optimizing the volatilization and condensation process of the solvent, and preventing the condensed solvent impurities from condensing back onto the OLED substrate and affecting the uniformity of film formation; the second vacuum pump is used to draw an extreme vacuum in the vacuum chamber, so that the condensed solvent impurities can be completely removed; the inkjet printing substrate vacuum drying equipment provided by the present invention shows significant beneficial effects in vacuum control, solvent volatilization and condensation, and solvent removal, so that the film formation of the OLED substrate during vacuum drying can be more uniform.

[0016] As some sub-solutions of the above technical solution, the vacuum pipeline system includes a main pipe, a rough pumping pipeline, a first angle valve, a first pumping speed control valve, a fine pumping pipeline, a second angle valve, a second pumping speed control valve and a secondary pipe;

[0017] One end of the main pipe is connected to the first vacuum pump, the other end of the main pipe is connected to one end of the rough pumping pipe through the first angle valve, the other end of the rough pumping pipe is connected to one end of the auxiliary pipe, and the other end of the auxiliary pipe is connected to the bottom of the vacuum chamber; the first pumping speed control valve is installed on the rough pumping pipe;

[0018] One end of the fine pumping pipeline is connected to the main pipe, and the other end of the fine pumping pipeline is connected to the auxiliary pipe through the second angle valve. The fine pumping pipeline and the rough pumping pipeline are connected in parallel; the second pumping speed control valve is installed on the fine pumping pipeline.

[0019] As some sub-solutions of the above technical solution, one end of the auxiliary pipe is connected to the fine pumping pipe and the rough pumping pipe arranged in parallel, and the other end of the auxiliary pipe is divided into four branch pipes, which are respectively connected to the four corners of the bottom of the vacuum chamber.

[0020] As some sub-solutions of the above technical solution, the lifting module has two groups, and the two groups of lifting modules are respectively arranged on the left and right sides of the box body; the inkjet printing substrate vacuum drying equipment also includes a driving motor, a first gear box, a second gear box and a transmission shaft; the driving motor is connected to the first gear box in a transmission connection, the first gear box and the second gear box are connected to the two groups of lifting modules in a transmission connection through the transmission shaft, and the first gear box and the second gear box are respectively connected to the two groups of lifting modules in a transmission connection;

[0021] When the driving motor provides power to the first gearbox, the first gearbox synchronously transmits the power to the second gearbox through the transmission shaft, and the first gearbox and the second gearbox then transmit the received power to the two groups of lifting modules respectively.

[0022] As some sub-solutions of the above technical solution, the lifting module includes a lead screw, a nut, a slide rail, a slider, a connecting piece, a lifting bellows and a mounting piece; the lead screw is arranged in a vertical direction, a nut is arranged on the lead screw, the nut is fixedly connected to the slider, the slide rail is vertically installed on the outside of the box, the slider is slidably connected to the slide rail, the lifting bellows is vertically arranged, the slider is connected to the lower end of the lifting bellows through the connecting piece, and the upper end of the lifting bellows is connected to the mounting piece; the mounting piece is used to support the bearing platform;

[0023] The rotation of the lead screw drives the nut to move up and down along the lead screw, so that the slider connected to the nut slides up and down along the slide rail. The slider then drives the lifting bellows and the mounting member to move up and down through the connecting member, thereby driving the load-bearing platform placed on the mounting member to move up and down.

[0024] As some sub-schemes of the above technical scheme, it also includes a heating liquid pipeline, a hot plate thermostat, a condensing liquid pipeline and a cold plate thermostat; the heating liquid pipeline is installed below the heating plate, and the hot plate thermostat is connected to the heating plate through the heating liquid pipeline; the condensing liquid pipeline is installed above the condensing plate, and the cold plate thermostat is connected to the condensing plate through the condensing liquid pipeline.

[0025] As some sub-solutions of the above technical solution, a product entrance and exit is provided on the side of the box body.

[0026] As some sub-solutions of the above technical solution, a cover opening mechanism is provided above the box body, and the cover opening mechanism is used to open the upper cover of the box body.

[0027] As some sub-solutions of the above technical solution, it also includes an electric control cabinet, which is arranged on the rack and is used to control all electric control products on the equipment.

[0028] A second aspect of the present invention provides a vacuum drying method for the inkjet printing substrate vacuum drying device described in the above embodiment, the vacuum drying method comprising the following steps:

[0029] The OLED substrate is placed in a vacuum chamber;

[0030] The first vacuum pump pumps the pressure in the vacuum chamber to the set value of the volatilization gas pressure, and at the same time, the heating plate is heated to the set value of the volatilization temperature, and the condensation plate is cooled to the set value of the condensation temperature; the distance between the heating plate and the condensation plate is adjusted, and the chamber pressure and temperature are maintained for a period of time, so that the ink solvent in the pixel groove of the substrate is volatilized and condensed on the condensation plate;

[0031] After the solvent condensation is completed, the first vacuum pump continues to evacuate to the set value of the film forming pressure, and at the same time, the heating plate changes its temperature to the set value of the film forming temperature, and the distance between the heating plate and the condensation plate is adjusted to perform high-temperature film forming;

[0032] After the film formation is completed, the second vacuum pump is turned on to reduce the pressure in the chamber to the minimum, and at the same time, all the solvents in the chamber are pumped out to clean the chamber;

[0033] Break the vacuum and take out the OLED substrate.

[0034] The beneficial effects of the second aspect of the embodiment of the present invention are as follows: based on the vacuum drying method of the above-mentioned inkjet printing substrate vacuum drying equipment, a three-stage vacuum pumping is adopted, so that the ink on the substrate will not be contaminated by the solvent when it is drying and forming a film, and because the temperature and air pressure suitable for solvent volatilization and ink film formation are adjusted in a targeted manner, the two processes of solvent volatilization and ink film formation are more effective, and the final film formation uniformity is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0036] Figure 1 A schematic diagram of the structure of a vacuum drying device for inkjet printing substrates provided in an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the structure of the vacuum pipeline system provided by the present invention;

[0038] Figure 3 A schematic diagram of the structure of a load-bearing platform provided in an embodiment of the present invention;

[0039] Figure 4 This is a structural schematic diagram of the lifting module provided by the present invention.

[0040] In the attached figure:

[0041] 1- rack;

[0042] 2-Box; 21-Product entrance and exit; 22-Electric control cabinet; 23-Opening mechanism;

[0043] 3-first vacuum pump; 31-second vacuum pump;

[0044] 4-vacuum pumping pipeline system; 41-main pipe; 42-rough pumping pipeline; 421-first angle valve; 422-first pumping speed control valve; 43-fine pumping pipeline; 431-second angle valve; 432-second pumping speed control valve; 44-auxiliary pipe;

[0045] 5-Carrying platform;

[0046] 6-heating plate; 61-heating liquid pipeline; 62-hot plate thermostat;

[0047] 7-condensation plate; 71-condensation liquid pipeline; 72-cold plate thermostat;

[0048] 8-driving motor; 81-first gear box; 82-transmission shaft; 83-second gear box;

[0049] 9-lifting module; 91-screw; 92-nut; 93-slide rail; 94-slider; 95-connecting piece; 96-lifting bellows; 97-installing piece. DETAILED DESCRIPTION

[0050] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0051] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0052] In the description of the present invention, the meaning of "several" is an indefinite quantity, the meaning of "multiple" is more than two, "greater than", "less than", "exceed", etc. are understood as not including the number itself, and "above", "below", "within", etc. are understood as including the number itself. If there is a description of the first and the second, it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. The "and / or" that appears in the full text represents three parallel solutions. For example, A and / or B represents the solution satisfied by A, the solution satisfied by B, or the solution satisfied by both A and B.

[0053] In the description of the present invention, if there is a short sentence containing multiple parallel features, the attributive defines the closest feature, for example: B, C, and E connected to D are arranged on A, which means that B is arranged on A and E is connected to D, and does not constitute a limitation on C; but attributives that indicate the relationship between features, such as "interval arrangement" or "circular arrangement", do not belong to this category. If the word "all" is preceded by an attributive, it means that all features in the short sentence are limited, such as B, C, and D are all arranged on A, which means that B, C, and D are all arranged on A. For a sentence with an omitted subject, the omitted subject is the subject of the previous sentence, that is, B is arranged on A, including C, which means that B is arranged on A and A includes C.

[0054] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0055] Combine the following Figures 1 to 4 Embodiments of the present invention are described.

[0056] Embodiment 1 provides a vacuum drying device for inkjet printing substrates, comprising:

[0057] Rack 1;

[0058] A box body 2 is arranged on the frame 1, and a vacuum cavity is provided inside the box body 2;

[0059] A first vacuum pump 3, disposed outside the vacuum chamber, and used for initially evacuating the vacuum chamber;

[0060] A vacuum pipe system 4, one end of which is connected to the first vacuum pump 3, and the other end of which is connected to the bottom of the vacuum chamber;

[0061] A second vacuum pump 31 is provided outside the vacuum chamber, and the second vacuum pump 31 is used to evacuate the vacuum chamber to the extreme vacuum;

[0062] The carrying platform 5 is arranged in the vacuum chamber; the carrying platform 5 is used to carry the material to be dried;

[0063] A lifting module 9 is provided on the box body 2, and the lifting module 9 is used to drive the carrying platform 5 to rise and fall;

[0064] A heating plate 6 is provided on the carrying platform 5, and the heating plate 6 is used to heat the material on the carrying platform 5;

[0065] The condensation plate 7 is disposed in the vacuum chamber and located above the carrying platform 5 . The condensation plate 7 is used to condense the volatilized solvent.

[0066] During the vacuum drying operation, the first vacuum pump 3 cooperates with the vacuum pipe system 4 to achieve efficient and precise control of the air pressure in the vacuum chamber, providing an ideal pressure environment for the drying and film-forming process of the OLED substrate; through the precise control of the lifting module 9, the distance between the heating plate 6 and the condensing plate 7 can be flexibly adjusted, thereby optimizing the volatilization and condensation process of the solvent, preventing the condensed solvent impurities from condensing back onto the OLED substrate and affecting the uniformity of film formation; the second vacuum pump 31 is used to draw an extreme vacuum to the vacuum chamber, so that the condensed solvent impurities can be completely removed.

[0067] Specifically, the vacuum pipeline system 4 includes a main pipe 41, a rough pumping pipe 42, a first angle valve 421, a first pumping speed control valve 422, a fine pumping pipe 43, a second angle valve 431, a second pumping speed control valve 432 and a secondary pipe 44;

[0068] One end of the main pipe 41 is connected to the first vacuum pump 3, the other end of the main pipe 41 is connected to one end of the rough pumping pipe 42 through the first angle valve 421, the other end of the rough pumping pipe 42 is connected to one end of the auxiliary pipe 44, and the other end of the auxiliary pipe 44 is connected to the bottom of the vacuum chamber; the first pumping speed control valve 422 is installed on the rough pumping pipe 42;

[0069] One end of the fine pumping pipeline 43 is connected to the main pipe 41 , and the other end of the fine pumping pipeline 43 is connected to the auxiliary pipe 44 through a second angle valve 431 . The fine pumping pipeline 43 and the rough pumping pipeline 42 are connected in parallel; a second pumping speed control valve 432 is installed on the fine pumping pipeline 43 .

[0070] The rough pumping pipeline 42 and the fine pumping pipeline 43 are connected in parallel, and different pipelines can be selected for vacuuming by switching the first angle valve 421 or the second angle valve 431; a first pumping speed control valve 422 is provided on the rough pumping pipeline 42, and a second pumping speed control valve 432 is provided on the fine pumping pipeline 43; when vacuuming, the first vacuum pump 3 is started first, and the first angle valve 421 is opened. The first vacuum pump 3 performs vacuuming through the rough pumping pipeline 42. At this time, the vacuuming rate can be controlled by the first pumping speed control valve 422. The diameter of the rough pumping pipeline 42 is larger than that of the fine pumping pipeline 43, and the vacuuming efficiency is faster. When the vacuum degree of the vacuum chamber is about to reach the set vacuum value , close the first angle valve 421 and the first pumping speed control valve 422, open the second angle valve 431 and the second pumping speed control valve 432, at this time the first vacuum pump 3 switches to vacuuming through the fine pumping pipe 43, and controls the vacuuming rate through the second pumping speed control valve 432; the fine pumping pipe 43 is finer and can better control the flow rate, which is convenient for stabilizing the vacuum degree inside the vacuum chamber, and is more effective when used in situations where fine control of vacuuming is required; during the vacuuming process, the vacuum degree is first pumped to near the set value using the rough pumping pipe 42, and then the fine pumping pipe 43 is used to stabilize the vacuum degree inside the chamber, so that the vacuum pressure in the vacuum chamber can be well controlled.

[0071] Specifically, one end of the auxiliary pipe 44 is connected to the fine pumping pipe 43 and the rough pumping pipe 42 arranged in parallel, and the other end of the auxiliary pipe 44 is divided into four branch pipes, which are respectively connected to the four corners of the bottom of the vacuum chamber.

[0072] One end of the auxiliary pipe 44 is divided into four branch pipes of equal size, and the four branch pipes are respectively connected to the lower part of the vacuum chamber. This is conducive to uniform distribution of flow velocity inside the vacuum chamber during vacuuming, reducing the impact on the product during vacuuming, and the product will not be damaged or displaced due to excessive flow velocity.

[0073] Specifically, the lifting module 9 has two groups, and the two groups of lifting modules 9 are respectively arranged on the left and right sides of the box body 2; the inkjet printing substrate vacuum drying equipment also includes a driving motor 8, a first gear box 81, a second gear box 83 and a transmission shaft 82; the driving motor 8 is connected to the first gear box 81 by transmission, the first gear box 81 and the second gear box 83 are connected to the two groups of lifting modules 9 by transmission through the transmission shaft 82, and the first gear box 81 and the second gear box 83 are connected to the two groups of lifting modules 9 by transmission respectively;

[0074] When the driving motor 8 provides power to the first gear box 81, the first gear box 81 transmits the power to the second gear box 83 synchronously through the transmission shaft 82, and the first gear box 81 and the second gear box 83 transmit the received power to the two groups of lifting modules 9 respectively. This transmission design ensures that the power can be evenly and stably distributed to both sides, and the two groups of lifting modules 9 can work synchronously and smoothly. For large-sized substrates, the lifting devices arranged on both sides of the box body 2 can make the substrate lifting more stable, effectively improving the stability and safety of the inkjet printed substrate during the vacuum drying process.

[0075] Specifically, the lifting module 9 includes a lead screw 91, a nut 92, a slide rail 93, a slider 94, a connector 95, a lifting bellows 96 and a mounting member 97; the lead screw 91 is arranged in the vertical direction, a nut 92 is arranged on the lead screw 91, the nut 92 is fixedly connected to the slider 94, the slide rail 93 is vertically installed on the outside of the box body 2, the slider 94 is slidably connected to the slide rail 93, the lifting bellows 96 is vertically arranged, the slider 94 is connected to the lower end of the lifting bellows 96 through the connector 95, and the upper end of the lifting bellows 96 is connected to the mounting member 97; the mounting member 97 is used to support the bearing platform 5;

[0076] The rotation of the lead screw 91 drives the nut 92 to move up and down along the lead screw 91, so that the slider 94 connected to the nut 92 slides up and down along the slide rail 93. The slider 94 then drives the lifting bellows 96 and the mounting member 97 to move up and down through the connecting member 95, thereby driving the supporting platform 5 placed on the mounting member 97 to move up and down.

[0077] It should be noted that the lead screw 91 is connected to the gear box in a transmission manner, and the drive motor 8 provides power to the lead screw 91 through the gear box. The rotation of the lead screw 91 drives the nut 92 thereon and the slider 94 connected to the nut 92 to move up and down along the lead screw 91. The slide rail 93 is vertically installed on the outside of the box body 2, providing a stable and precise sliding track for the slider 94 to prevent the nut 92 and the slider 94 from shifting; the connecting piece 95 connects the slider 94 to the lower end of the lifting bellows 96, and the up and down sliding of the slider 94 can be converted into the up and down lifting of the lifting bellows 96; the lifting bellows 96, as a flexible connecting piece 95, has good elasticity, and can also absorb some vibration and impact, making the lifting process smoother; and the lifting bellows 96 has good sealing performance, which can ensure that the vacuum degree of the vacuum chamber will not be affected by gas leakage during the lifting process.

[0078] Specifically, the inkjet printing substrate vacuum drying equipment also includes a heating liquid pipeline 61, a hot plate thermostat 62, a condensing liquid pipeline 71 and a cold plate thermostat 72; the heating liquid pipeline 61 is installed below the heating plate 6, and the hot plate thermostat 62 is connected to the heating plate 6 through the heating liquid pipeline 61; the condensing liquid pipeline 71 is installed above the condensing plate 7, and the cold plate thermostat 72 is connected to the condensing plate 7 through the condensing liquid pipeline 71. The heating liquid pipeline 61 is installed below the heating plate 6, which will not block the volatilization of the solvent in the material on the carrying platform 5. The local overheating or uneven temperature problems that may be caused by the traditional direct heating method can be transferred more evenly by using the heating pipeline; the hot plate thermostat 62 is connected to the heating plate 6 through the heating liquid pipeline 61, and can monitor and adjust the temperature of the heating plate 6 in real time to achieve precise temperature control; the condensing liquid pipeline 71 is installed above the condensing plate 7, which will not block the condensation of the volatilized solvent on the condensing plate 7. Secondly, the introduction of the cold plate thermostat 72 and the condensing liquid pipeline 71 makes the temperature control of the condensing plate 7 more stable.

[0079] The side of the box body 2 is provided with a product inlet and outlet 21. When a product comes in, the gate valve of the product inlet and outlet 21 opens, and the product is sent into the vacuum main cavity. When the product is processed, the gate valve of the product inlet and outlet 21 opens, and the product can be taken out from the inlet and outlet.

[0080] A cover opening mechanism 23 is provided above the box body 2, and the cover opening mechanism 23 is used to open the upper cover of the box body 2. Because the vacuum pipe system 4 of the traditional vacuum drying equipment is arranged above the box body 2, it is difficult to clean the box body 2. The box body 2 of the present invention is provided with a cover opening device, which can open the box body 2 and facilitate cleaning and maintenance of the vacuum chamber.

[0081] The inkjet printed substrate vacuum drying equipment also includes an electric control cabinet 22, which is arranged on the frame 1. The electric control cabinet 22 is used to control all electronic control products on the equipment, such as controlling the operation of the vacuum pump, the operation of the drive motor 8 in the lifting mechanism, the operation of the cold plate temperature controller 72 and the hot plate temperature controller 62, and the vacuum signal collection inside the vacuum chamber.

[0082] Embodiment 2

[0083] A vacuum drying method, the vacuum drying method comprising the following steps:

[0084] The OLED substrate is placed in a vacuum chamber;

[0085] The first vacuum pump 3 pumps the pressure in the vacuum chamber to the set value of the volatilization gas pressure, and at the same time, the heating plate 6 is heated to the set value of the volatilization temperature, and the condensation plate 7 is cooled to the set value of the condensation temperature; the distance between the heating plate 6 and the condensation plate 7 is adjusted, and the chamber pressure and temperature are maintained for a period of time, so that the ink solvent in the pixel groove of the substrate is volatilized and condensed on the condensation plate 7;

[0086] After the solvent condensation is completed, the first vacuum pump 3 continues to evacuate to the set value of the film forming pressure, and at the same time, the heating plate 6 changes its temperature to the set value of the film forming temperature, and the distance between the heating plate 6 and the condensing plate 7 is adjusted to perform high-temperature film forming;

[0087] After the film formation is completed, the second vacuum pump 31 is turned on to reduce the pressure in the cavity to the minimum, and at the same time, all the solvent in the cavity is pumped out to clean the cavity;

[0088] Break the vacuum and take out the OLED substrate.

[0089] Conventional vacuum dryers generally have only one vacuuming process, that is, the vacuum drying and ink film forming steps are completed in one vacuuming process. The volatilization and condensation of the solvent may cause cross contamination, and there is a lack of air pressure control and heat preservation control, so the solute film is not uniform. Therefore, the present invention sets a three-stage vacuuming process in the OLED substrate drying process;

[0090] The first stage of vacuuming: the first vacuum pump 3 pumps the pressure in the vacuum chamber to the set value of the volatilization pressure, and at the same time, the heating plate 6 is heated to the set value of the volatilization temperature, and the condensation plate 7 is cooled to the set value of the condensation temperature; at this time, the air pressure in the vacuum chamber is the air pressure suitable for the volatilization of the solvent, the temperature of the heating plate 6 is the temperature suitable for the volatilization of the solvent, and the temperature of the condensation plate 7 is the temperature suitable for the condensation of the solvent, which can enhance the effect of solvent volatilization and condensation; then adjust the distance between the heating plate 6 and the condensation plate 7 so that the volatilized solvent can contact the condensation plate 7 and complete condensation on the condensation plate 7; the pressure and temperature in the vacuum chamber will be maintained for a period of time, so that the ink solvent in the pixel groove of the substrate can fully volatilize and complete condensation on the condensation plate 7;

[0091] The second stage of vacuuming: after the solvent condensation is completed, the first vacuum pump 3 continues to vacuum to the set value of the film forming pressure, and at the same time, the heating plate 6 changes its temperature to the set value of the film forming temperature. The air pressure in the vacuum chamber is the air pressure suitable for ink film formation, and the temperature of the heating plate 6 is the temperature suitable for ink film formation; the distance between the heating plate 6 and the condensation plate 7 is adjusted to prevent the solvent on the condensation plate 7 from being volatilized back to the substrate due to high temperature and causing contamination; then the heating plate 6 maintains the temperature at the set value of the film forming temperature, so that the ink on the substrate is subjected to high-temperature film formation;

[0092] The third stage of vacuuming: after the ink film is formed, the second vacuum pump 31 is turned on, and the second vacuum pump 31 reduces the pressure in the cavity to the minimum, and at the same time removes all the solvent in the cavity, completing the cavity cleaning;

[0093] Such three-stage vacuuming ensures that the ink on the substrate will not be contaminated by the solvent when it dries and forms a film. In addition, because the temperature and air pressure suitable for solvent evaporation and ink film formation are adjusted specifically, the effects of the two processes of solvent evaporation and ink film formation are better, and the final film formation is more uniform.

[0094] The preferred embodiments of the present invention are described in detail above, but the present disclosure is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present disclosure.

Claims

1. A vacuum drying method, characterized in that: The invention is applied to a vacuum drying device for an inkjet printing substrate, the vacuum drying device for an inkjet printing substrate comprising: a frame (1); a box (2) arranged on the frame (1), the box (2) having a vacuum cavity inside; a first vacuum pump (3) arranged outside the vacuum cavity, the first vacuum pump (3) being used for initially evacuating the vacuum cavity; a vacuum evacuation pipeline system (4), one end of the vacuum evacuation pipeline system (4) being connected to the first vacuum pump (3), and the other end of the vacuum evacuation pipeline system (4) being connected to the bottom of the vacuum cavity; a second vacuum pump (31) being arranged outside the vacuum cavity The second vacuum pump (31) is used to evacuate the vacuum chamber to the limit; the carrying platform (5) is arranged in the vacuum chamber; the carrying platform (5) is used to carry the material to be dried; the lifting module (9) is arranged on the box body (2), and the lifting module (9) is used to drive the carrying platform (5) to move up and down; the heating plate (6) is arranged on the carrying platform (5), and the heating plate (6) is used to heat the material on the carrying platform (5); the condensing plate (7) is arranged in the vacuum chamber and located above the carrying platform (5), and the condensing plate (7) is used to condense the volatilized solvent; The vacuum drying method comprises the following steps: The OLED substrate is placed in a vacuum chamber; The first vacuum pump (3) pumps the pressure in the vacuum chamber to a set value of the volatilization gas pressure, and at the same time, the heating plate (6) is heated to a set value of the volatilization temperature, and the condensation plate (7) is cooled to a set value of the condensation temperature; the distance between the heating plate (6) and the condensation plate (7) is adjusted, and the pressure and temperature of the chamber are maintained for a period of time, so that the ink solvent in the pixel groove of the substrate is volatilized and condensed on the condensation plate (7); After the solvent condensation is completed, the first vacuum pump (3) continues to evacuate to the set value of the film forming pressure, and at the same time, the heating plate (6) changes the temperature to the set value of the film forming temperature, and the distance between the heating plate (6) and the condensation plate (7) is adjusted to perform high-temperature film forming; After the film formation is completed, the second vacuum pump (31) is turned on to reduce the pressure in the cavity to a minimum, and at the same time, all the solvent in the cavity is pumped out to clean the cavity; Break the vacuum and take out the OLED substrate.

2. The vacuum drying method according to claim 1, characterized in that: The vacuum pumping pipeline system (4) comprises a main pipe (41), a rough pumping pipeline (42), a first angle valve (421), a first pumping speed control valve (422), a fine pumping pipeline (43), a second angle valve (431), a second pumping speed control valve (432) and a secondary pipe (44); One end of the main pipe (41) is connected to the first vacuum pump (3), the other end of the main pipe (41) is connected to one end of the rough extraction pipe (42) via the first angle valve (421), the other end of the rough extraction pipe (42) is connected to one end of the auxiliary pipe (44), and the other end of the auxiliary pipe (44) is connected to the bottom of the vacuum chamber; the first extraction speed control valve (422) is installed on the rough extraction pipe (42); One end of the fine pumping pipeline (43) is connected to the main pipeline (41), and the other end of the fine pumping pipeline (43) is connected to the auxiliary pipeline (44) via the second angle valve (431); the fine pumping pipeline (43) and the rough pumping pipeline (42) are connected in parallel; and the second pumping speed control valve (432) is installed on the fine pumping pipeline (43).

3. The vacuum drying method according to claim 2, characterized in that: One end of the auxiliary pipe (44) is connected to the fine pumping pipe (43) and the rough pumping pipe (42) which are arranged in parallel, and the other end of the auxiliary pipe (44) is divided into four branch pipes, which are respectively connected to the four corners of the bottom of the vacuum chamber.

4. The vacuum drying method according to claim 1, characterized in that: The lifting modules (9) have two groups, and the two groups of lifting modules (9) are respectively arranged on the left and right sides of the box body (2); the inkjet printing substrate vacuum drying equipment also includes a driving motor (8), a first gear box (81), a second gear box (83) and a transmission shaft (82); the driving motor (8) is transmission-connected to the first gear box (81), the first gear box (81) is transmission-connected to the second gear box (83) via the transmission shaft (82), and the first gear box (81) and the second gear box (83) are transmission-connected to the two groups of lifting modules (9) respectively; When the driving motor (8) provides power to the first gear box (81), the first gear box (81) synchronously transmits the power to the second gear box (83) via the transmission shaft (82), and the first gear box (81) and the second gear box (83) then respectively transmit the received power to the two sets of lifting modules (9).

5. The vacuum drying method according to claim 1, characterized in that: The lifting module (9) comprises a lead screw (91), a nut (92), a slide rail (93), a slider (94), a connecting piece (95), a lifting bellows (96) and a mounting piece (97); the lead screw (91) is arranged in a vertical direction, a nut (92) is provided on the lead screw (91), the nut (92) is fixedly connected to the slider (94), the slide rail (93) is vertically mounted on the outside of the box body (2), the slider (94) is slidably connected to the slide rail (93), the lifting bellows (96) is vertically arranged, the slider (94) is connected to the lower end of the lifting bellows (96) through the connecting piece (95), and the upper end of the lifting bellows (96) is connected to the mounting piece (97); the mounting piece (97) is used to support the bearing platform (5); The screw (91) rotates to drive the nut (92) to move up and down along the screw (91), causing a slider (94) connected to the nut (92) to slide up and down along the slide rail (93); the slider (94) then drives the lifting bellows (96) and the mounting member (97) to move up and down through the connecting member (95), thereby driving the bearing platform (5) placed on the mounting member (97) to move up and down.

6. The vacuum drying method according to claim 1, characterized in that: The inkjet printing substrate vacuum drying equipment further comprises a heating liquid pipeline (61), a hot plate temperature controller (62), a condensing liquid pipeline (71) and a cold plate temperature controller (72); the heating liquid pipeline (61) is installed below the heating plate (6), and the hot plate temperature controller (62) is connected to the heating plate (6) via the heating liquid pipeline (61); the condensing liquid pipeline (71) is installed above the condensing plate (7), and the cold plate temperature controller (72) is connected to the condensing plate (7) via the condensing liquid pipeline (71).

7. The vacuum drying method according to claim 1, characterized in that: A product inlet and outlet (21) is provided on the side of the box body (2).

8. The vacuum drying method according to claim 1, characterized in that: A cover opening mechanism (23) is provided above the box body (2), and the cover opening mechanism (23) is used to open the upper cover of the box body (2).

9. The vacuum drying method according to claim 1, characterized in that: The inkjet printing substrate vacuum drying equipment further comprises an electric control cabinet (22), wherein the electric control cabinet (22) is arranged on the frame (1), and the electric control cabinet (22) is used to control all electric control products on the equipment.

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