Vacuum drying film forming device and method

Abstract

The invention discloses a vacuum drying film forming device and method, and the device comprises a vacuum chamber which is configured to provide a variable-pressure environment; the bearing plate is configured to bear a condensation plate of a film forming substrate to be dried, is arranged above the bearing plate, is parallel to the bearing plate, and is configured to condense and capture a solvent evaporated from the film forming substrate; the bearing plate is configured to move in the direction perpendicular to the condensation plate so as to adjust the distance between the bearing plate and the condensation plate, and the pressure intensity in the vacuum cavity and the distance between the bearing plate and the condensation plate are synchronously and dynamically adjusted. And the space between the bearing plate and the condensation plate is basically kept at the saturated vapor pressure of the solvent all the time in the drying process of the film layer on the film forming substrate on the bearing plate.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of display semiconductor manufacturing technology, and particularly relates to a vacuum drying film-forming device and method, which is suitable for the printing preparation process of an OLED display panel, and particularly suitable for the low-temperature drying process after solution film-forming of an electron transport layer, a light-emitting layer, a hole transport layer, etc. BACKGROUND

[0002] In the preparation process of an organic electroluminescent device (OLED) display panel, the film-forming method of the core display layer, such as an electron transport layer, a light-emitting layer, and a hole transport layer, mainly includes an evaporation process and a solution process. The inkjet printing technology in the solution process is considered an important way to realize mass production of large-size OLED display panels because of its high material utilization rate and the ability to realize large-size.

[0003] The process of the current inkjet printing technology includes an inkjet printing (IJP) process, a vacuum drying process, and a baking process. In the vacuum drying process, the ink drop drying speed on the substrate to be dried and the uniformity of solvent evaporation have an important influence on the final morphology of the thin film, and the thin film morphology directly affects the display effect of the OLED display panel. SUMMARY

[0004] An aspect of the present disclosure aims to solve the problem of uneven film-forming caused by large temperature gradient, local overheating, and solvent redeposition in the traditional drying methods such as hot plate, hot air, or infrared heating.

[0005] Some embodiments of the present disclosure provide a vacuum drying film-forming device, which comprises:

[0006] a vacuum chamber configured to provide a variable pressure environment;

[0007] a carrier plate configured to carry a film-forming substrate to be dried;

[0008] a condensing plate arranged above the carrier plate and parallel to the carrier plate, configured to condense and capture solvent evaporated from the film-forming substrate;

[0009] The carrier plate is configured to move in a direction perpendicular to the condensing plate to adjust the distance between the carrier plate and the condensing plate. The pressure in the vacuum chamber and the distance between the carrier plate and the condensing plate are dynamically adjusted synchronously, so that the space between the carrier plate and the condensing plate is basically always at the saturation vapor pressure of the solvent during the drying process of the film layer on the film-forming substrate on the carrier plate.

[0010] In some embodiments, the vacuum drying film-forming device further comprises:

[0011] A dry pump, connected to the vacuum chamber, configured to reduce the pressure in the vacuum chamber from atmospheric pressure to a first pressure greater than the saturated vapor pressure of the solvent; and

[0012] A molecular pump, connected to the vacuum chamber, is configured to reduce the pressure in the vacuum chamber from a first pressure to a second pressure, the second pressure being lower than the saturated vapor pressure of the solvent.

[0013] In some embodiments, the vacuum drying film-forming apparatus further includes a servo-driven linear actuator, the servo-driven linear actuator comprising:

[0014] A support assembly extends through the bottom of the vacuum chamber and supports the bottom of the carrier plate.

[0015] A drive motor drives the support link to move in a direction perpendicular to the condenser plate to adjust the distance between the support plate and the condenser plate.

[0016] In some embodiments, the temperature of at least one of the support plate and the condenser plate is adjustable.

[0017] This disclosure provides a vacuum drying film formation method according to some embodiments, the vacuum drying film formation method comprising the following steps:

[0018] The substrate to be dried and formed into a film is transferred to a carrier plate in a vacuum chamber;

[0019] The pressure inside the vacuum chamber and the distance between the support plate and the condenser plate are dynamically adjusted synchronously so that the space between the support plate and the condenser plate is basically always at the saturated vapor pressure of the solvent evaporated from the film-forming substrate during the drying process of the film layer on the film-forming substrate.

[0020] The dried film-forming substrate is transferred out of the vacuum chamber.

[0021] In some embodiments, the synchronous dynamic adjustment of the pressure inside the vacuum chamber and the distance between the support plate and the condenser plate includes the following steps:

[0022] The pressure reduction phase operation is performed, reducing the distance between the support plate and the condenser plate to a first distance, while simultaneously reducing the pressure of the vacuum chamber to a second pressure in stages;

[0023] During the pressure stabilization and drying phase, while maintaining the vacuum chamber at the second pressure state, the distance between the support plate and the condenser plate is gradually increased to the second distance; and

[0024] The pressurization phase is executed to restore the vacuum chamber pressure to atmospheric pressure and adjust the distance between the support plate and the condenser plate to the initial distance.

[0025] In some embodiments, the step of performing the pressure reduction phase operation, reducing the distance between the support plate and the condenser plate to a first distance, and simultaneously reducing the pressure of the vacuum chamber to a second pressure in stages, includes the following steps:

[0026] The distance between the support plate and the condenser plate is decreased at a constant speed, so that the distance between the support plate and the condenser plate is reduced from the initial distance to the first distance;

[0027] A dry pump is used to reduce the pressure inside the vacuum chamber from atmospheric pressure to a first pressure, which is greater than the saturated vapor pressure of the solvent.

[0028] A molecular pump is used to reduce the pressure in the vacuum chamber from a first pressure to a second pressure, where the second pressure is less than the saturated vapor pressure of the solvent.

[0029] In some embodiments, reducing the pressure in the vacuum chamber from atmospheric pressure to a first pressure, where the first pressure is greater than the saturated vapor pressure of the solvent, using a dry pump includes the following steps:

[0030] Low-speed depressurization operation: The pressure in the vacuum chamber is reduced from atmospheric pressure to a third pressure at a low speed using a dry pump.

[0031] High-speed pressure reduction operation: The pressure in the vacuum chamber is rapidly reduced from the third pressure to the first pressure using a dry pump.

[0032] The moment when the distance between the support plate and the condenser plate decreases to the first distance occurs during the low-speed depressurization operation.

[0033] In some embodiments, the step of performing the pressure-stabilizing drying stage, while maintaining the vacuum chamber at a first pressure state, gradually increasing the distance between the support plate and the condenser plate to a second distance includes the following steps:

[0034] After the space between the support plate and the condenser plate is at the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is continuously adjusted so that the distance between the support plate and the condenser plate increases from the first distance to the second distance.

[0035] In some embodiments, the step of performing the pressure-stabilizing drying stage, while maintaining the vacuum chamber at a first pressure state, gradually increasing the distance between the support plate and the condenser plate to a second distance includes the following steps:

[0036] After the space between the support plate and the condenser plate reaches the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is adjusted in stages so that the distance between the support plate and the condenser plate increases from a first distance to a second distance.

[0037] The vacuum drying film-forming apparatus disclosed herein allows for precise control of the vacuum chamber pressure and the distance between the support plate and the condenser plate. By synchronously and dynamically adjusting the pressure within the vacuum chamber and the distance between the support plate and the condenser plate, the space between the support plate and the condenser plate remains essentially at the saturated vapor pressure of the solvent during the drying process of the film layer on the film-forming substrate on the support plate. This enables rapid, uniform, and clean drying of the film layer at low temperatures, avoiding defects such as drying mura, material performance degradation, and warping of large-size glass substrates, thus meeting the mass production requirements of precision printed displays. Attached Figure Description

[0038] Figure 1 This is a schematic diagram illustrating a scenario for preparing a film-forming substrate to be dried, as provided in some embodiments of this disclosure.

[0039] Figure 2 This is a schematic diagram of a vacuum drying film-forming apparatus for some embodiments of the present disclosure.

[0040] Figure 3 A schematic diagram of the structure of a servo-driven linear actuator provided in some embodiments of this disclosure is shown.

[0041] Figure 4 A flowchart of a vacuum film formation method provided for some embodiments of this disclosure.

[0042] Figure 5 for Figure 4 The detailed flowchart of step S20.

[0043] Figure 6 for Figure 5 The detailed flowchart of step S21.

[0044] Figure 7 for Figure 6 The detailed flowchart of step S212.

[0045] Figure 8 A schematic diagram of parameter curves for the low-temperature vacuum drying process of the OLED functional layer provided in this embodiment is shown. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0047] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The singular forms “a,” “the,” and “the” as used in the embodiments of this disclosure and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0048] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0049] It should be understood that although the terms first, second, third, etc. may be used to describe the embodiments in this disclosure, it should not be limited to these terms.

[0050] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the article or device that includes said element.

[0051] In related technologies, when the substrate to be dried is dried in a low-pressure environment in a vacuum chamber, the gap between the support plate and the condensation plate supporting the substrate is fixed, leading to the following process problems:

[0052] First, the solvent evaporation rate is uneven. In the initial stage of drying, the solvent content is high and the vapor partial pressure is large. If the gap is too small, the gas flow is restricted, which can easily lead to local solvent retention, resulting in uneven film surface temperature and evaporation rate. If the gap is too large, the condensation efficiency will be reduced, and the solvent evaporation will be greatly affected by the airflow, thus affecting the film formation process.

[0053] Second, the solvent vapor extraction efficiency decreases. The fixed gap cannot automatically adjust the relative distance between the condenser plate and the support plate according to different evaporation stages. When the solvent evaporation rate is high, if the condenser plates are too close, some solvent molecules may diffuse back to the film surface.

[0054] Third, the uniformity of the film layer is limited. Because the concentration of solvent vapor in the airflow field is difficult to maintain a stable equilibrium under a fixed gap, local dead zones or accumulation zones may be generated, resulting in uneven film thickness, Mura defects, and drying edge effects.

[0055] Fourth, it cannot accommodate different materials and solvent systems. Different ink systems (high-boiling-point or low-boiling-point solvents) have different optimal conditions for vacuum degree and gap height. A fixed gap cannot meet the process window requirements of various materials, reducing the versatility of the equipment.

[0056] Fifth, the drying time and energy consumption increase. Under non-optimal gap conditions, the solvent transport path becomes longer or the condensation efficiency decreases, resulting in a decrease in the overall drying rate, an increase in the vacuum chamber pumping load, and an increase in system energy consumption.

[0057] To overcome the above problems, this disclosure provides a vacuum drying film-forming apparatus, comprising: a vacuum chamber configured to provide a variable pressure environment; a support plate configured to support a substrate to be dried and film-forming; and a condenser plate disposed above the support plate and parallel to the support plate, configured to condense solvent evaporated from the film-forming substrate; the support plate is configured to move in a direction perpendicular to the condenser plate to adjust the distance between the support plate and the condenser plate, and the pressure in the vacuum chamber and the distance between the support plate and the condenser plate are dynamically adjusted synchronously, so that during the drying process of the film layer on the film-forming substrate on the support plate, the space between the support plate and the condenser plate is essentially always at the saturated vapor pressure of the solvent.

[0058] The vacuum drying film-forming apparatus disclosed herein allows for precise control of the vacuum chamber pressure and the distance between the support plate and the condenser plate. By synchronously and dynamically adjusting the pressure within the vacuum chamber and the distance between the support plate and the condenser plate, the space between the support plate and the condenser plate remains essentially at the saturated vapor pressure of the solvent during the drying process of the film layer on the film-forming substrate on the support plate. This enables rapid, uniform, and clean drying of the film layer at low temperatures, avoiding defects such as Mura defects, material performance degradation, and warping of large-size glass substrates, thus meeting the mass production requirements of precision printed displays.

[0059] The optional embodiments of this disclosure are described in detail below with reference to the accompanying drawings.

[0060] Figure 1 This is a schematic diagram illustrating the fabrication scenario of a substrate to be dried for film formation, provided in some embodiments of this disclosure. The pixel structure of an OLED display panel is composed of OLED devices corresponding to each pixel. The OLED device layer structure typically includes a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL). These layers are typically fabricated using inkjet printing processes, such as... Figure 1 As shown. The film-forming substrate formed by inkjet printing is dried using a vacuum drying (VCD) process.

[0061] Figure 2This is a schematic diagram of a vacuum drying film-forming apparatus for some embodiments of the present disclosure. For example... Figure 2 As shown, some embodiments of this disclosure provide a vacuum drying film forming apparatus 100, which includes a vacuum chamber 10, a support plate 20, and a condenser plate 30.

[0062] Vacuum chamber 10, such as a sealable chamber, is configured to provide a variable pressure environment, providing a near-vacuum low-pressure environment for the drying process of the film-forming substrate S to be dried. Support plate 20 is configured to support the film-forming substrate S to be dried. Condenser plate 30 is disposed above and parallel to the support plate 20, configured to condense and capture solvent evaporating from the film-forming substrate S.

[0063] The support plate 20 is configured to move in a direction perpendicular to the condenser plate, such as direction X, to adjust the distance between the support plate 20 and the condenser plate 30. In some embodiments, the condenser plate 30 is located in a fixed position in the vacuum chamber, and the support plate 20 can move toward or away from the condenser plate 30.

[0064] The pressure within the vacuum chamber 10 and the distance between the support plate 20 and the condenser plate 30 are dynamically adjusted synchronously, ensuring that the space between the support plate 20 and the condenser plate 30 remains essentially at the saturated vapor pressure of the solvent throughout the drying process of the film layer on the film-forming substrate S on the support plate 20. Under these conditions, the drying speed of each region of the film-forming substrate S is essentially uniform, resulting in uniform and rapid film formation.

[0065] The vacuum drying film-forming apparatus in this embodiment, by synchronously and dynamically adjusting the pressure inside the vacuum chamber and the distance between the support plate and the condenser plate, ensures that during the drying process of the film layer on the film-forming substrate on the support plate, the space between the support plate and the condenser plate is basically always at the saturated vapor pressure of the solvent. This enables the film layer to dry quickly, uniformly, and cleanly at low temperatures, avoiding defects such as Mura defects, material performance degradation, and warping of large-size glass substrates, thus meeting the mass production requirements of precision printed displays.

[0066] In some embodiments, such as Figure 2 As shown, the vacuum drying film-forming apparatus 100 also includes vacuum pumps 40, for example, two vacuum pumps symmetrically arranged on both sides of the vacuum chamber 10, to extract gas from the vacuum chamber 10 to achieve low pressure. Specifically, the vacuum pumps 40 include a dry pump and a molecular pump, which are used together and can be in series or parallel mode.

[0067] A dry pump is connected to the vacuum chamber 10 and configured to reduce the pressure in the vacuum chamber 10 from atmospheric pressure to a first pressure, which is greater than the saturated vapor pressure of the solvent. A molecular pump is connected to the vacuum chamber 10 and configured to reduce the pressure in the vacuum chamber 10 from the first pressure to a second pressure, which is lower than the saturated vapor pressure of the solvent. The combination of the dry pump and the molecular pump reduces the pressure in the vacuum chamber to below the saturated vapor pressure of the solvent, which facilitates the rapid low-temperature evaporation of the solvent in the film layer on the film-forming substrate.

[0068] In some embodiments, the vacuum drying film-forming apparatus 100 further includes a servo-driven linear actuator 50, which is configured to drive the support plate 30 to move in a direction perpendicular to the condenser plate. For example, there are four servo-driven linear actuators 50, which support the four corners of the support plate 30 respectively. The four servo-driven linear actuators 50 operate synchronously to control the support plate 30 to always be in a state parallel to the condenser plate 20, moving closer to or further away from the condenser plate 20, and precisely controlling the distance between the support plate 30 and the condenser plate 20.

[0069] Figure 3 A schematic diagram of the structure of a servo-driven linear actuator provided in some embodiments of this disclosure is shown. For example... Figure 3 As shown, the servo-driven linear actuator 50 includes a support assembly and a drive motor 52. The support assembly passes through the bottom of the vacuum chamber 10 and supports the bottom of the carrier plate 30. The drive motor 52 drives the support assembly to move in a direction perpendicular to the condenser plate to adjust the distance between the carrier plate 30 and the condenser plate 20. The support assembly includes a fixed sleeve 53 and a hot water supply pipe 51. The fixed sleeve 53 supports the carrier plate 30 to achieve a lifting action. The hot water supply pipe 51 is located inside the fixed sleeve 53 and connected to the carrier plate 30, providing a circulating fluid heat source for the carrier plate 30 to uniformly control the temperature of the carrier plate 30.

[0070] The servo-driven linear actuator 50 also includes a bellows 54 and a moving platform 55. The bellows 54 is fitted over the fixed sleeve 53 to provide a sealed environment, ensuring that the environment of the fixed sleeve 53 and the cavity 10 is consistent and there are no air leaks. The moving platform 55 is connected to the bottom of the vacuum chamber and supports the vacuum chamber 10. It provides support for the entire lifting assembly.

[0071] In some embodiments, at least one of the support plate 30 and the condenser plate 20 is temperature-adjustable. The support plate 30, for example, provides heat to the film-forming substrate S it supports, and its temperature is adjustable to control the temperature of the film-forming substrate S, thereby regulating the evaporation rate of the solvent in the film layer on the film-forming substrate S. The condenser plate 20 provides an adjustable condensation temperature to control the condensation rate of the solvent gas. By creating a near-vacuum low pressure in the vacuum chamber 10, and cooperating with the condenser plate 20 to capture the solvent through condensation, low-temperature drying of the film layer on the film-forming substrate S can be achieved without providing a high temperature to the film-forming substrate S.

[0072] Some embodiments of this disclosure also provide a vacuum drying film formation method, which uses the vacuum film formation apparatus in the foregoing embodiments. Figure 4 Here is a flowchart of a vacuum film formation method provided in some embodiments of this disclosure, such as... Figure 4 As shown, the vacuum drying film formation method includes the following steps:

[0073] S10: Transfer the substrate to be dried and formed into a film onto the carrier plate in the vacuum chamber;

[0074] Specifically, a robotic arm or other conveying device is used to transfer the inkjet-printed substrate to a carrier plate in a vacuum chamber.

[0075] S20: Synchronously and dynamically adjust the pressure inside the vacuum chamber and the distance between the support plate and the condenser plate so that during the drying process of the film layer on the film-forming substrate, the space between the support plate and the condenser plate is basically always at the saturated vapor pressure of the solvent evaporated from the film-forming substrate.

[0076] Specifically, the pressure of the vacuum chamber in the vacuum drying film-forming device can be precisely controlled, as can the distance between the support plate and the condenser plate. By synchronously and dynamically adjusting the pressure in the vacuum chamber and the distance between the support plate and the condenser plate, the space between the support plate and the condenser plate is basically always at the saturated vapor pressure of the solvent during the drying process of the film layer on the film-forming substrate on the support plate. This enables the film layer to dry quickly, uniformly, and cleanly at low temperatures, avoiding defects such as Mura defects, material performance degradation, and warping of large-size glass substrates, thus meeting the mass production requirements of precision printed displays.

[0077] S30: Transfer the dried film-forming substrate out of the vacuum chamber.

[0078] Specifically, after the film-forming substrate completes the drying process, a robotic arm or other conveying device is used to move the dried film-forming substrate out of the vacuum chamber and transfer it to the next process.

[0079] In some embodiments, Figure 5 for Figure 4 The detailed flowchart of step S20 is as follows: Figure 5As shown, step S20: synchronously and dynamically adjusting the pressure inside the vacuum chamber and the distance between the support plate and the condenser plate includes the following steps:

[0080] S21: Perform the pressure reduction stage operation, reduce the distance between the support plate and the condenser plate to a first distance, and at the same time reduce the pressure of the vacuum chamber to a second pressure in stages.

[0081] Specifically, the space between the carrier plate and the condenser plate is rapidly constructed to create an environment with solvent saturated vapor pressure, providing conditions for low-temperature stable drying of the film. In this saturated vapor pressure environment, the solvent in the film layer on the film-forming substrate can evaporate uniformly and stably and be captured by the condenser plate. The first distance is, for example, 3 to 18 mm, and the second pressure is, for example, 0.01 Pa to 1 Pa. In some embodiments, the vacuuming process of the vacuum chamber can begin as the carrier plate moves towards the condenser plate.

[0082] S22: Perform the pressure stabilization and drying stage operation, while keeping the vacuum chamber in the second pressure state, gradually increase the distance between the support plate and the condenser plate to the second distance.

[0083] Specifically, during the pressure stabilization and drying stage, the distance between the support plate and the condenser plate is gradually increased to a second distance. This ensures that the space between the support plate and the condenser plate is maintained at a solvent saturation vapor pressure while gradually increasing. This guarantees that the solvent in the film layer on the film-forming substrate can evaporate uniformly and stably, while increasing the free path of the evaporating molecules and accelerating the evaporation rate. Most of the gaseous solvent from the evaporation is extracted from the space between the support plate and the condenser plate, preventing excessive accumulation of the evaporated solvent on the condenser plate, which would cause it to drop and increase the maintenance and cleaning cycle of the condenser plate. The second distance is, for example, 30 mm to 50 mm.

[0084] S23: Perform the pressurization phase operation, restore the vacuum chamber pressure to normal pressure, and adjust the distance between the support plate and the condenser plate to the initial distance.

[0085] Specifically, after the pressure stabilization and drying stage is completed, the film layer on the film-forming substrate has met the drying effect requirements. The vacuum chamber pressure is restored to atmospheric pressure, and the distance between the support plate and the condenser plate is adjusted to the initial distance so that a robotic arm or other conveying device can move the dried film-forming substrate out of the vacuum chamber and transfer it to the next process. The initial distance is, for example, 80mm to 100mm, and the atmospheric pressure is, for example, 10. 5 Pa.

[0086] In some embodiments, Figure 6 for Figure 5 The detailed flowchart of step S21 is as follows: Figure 6As shown, step S21: Performing the pressure reduction stage operation, reducing the distance between the support plate and the condenser plate to a first distance, and simultaneously reducing the pressure of the vacuum chamber to a second pressure in stages includes the following steps:

[0087] S211: The distance between the support plate and the condenser plate is reduced at a constant speed so that the distance between the support plate and the condenser plate is reduced from the initial distance to the first distance.

[0088] Specifically, a servo-driven linear actuator is used to maintain a relatively fast and uniform distance between the support plate and the condenser plate.

[0089] S212: The pressure inside the vacuum chamber is reduced from atmospheric pressure to a first pressure, which is greater than the saturated vapor pressure of the solvent, using a dry pump.

[0090] During the process of evacuating the vacuum chamber from atmospheric pressure, it is necessary to evacuate in stages. The dry pump can only pump the pressure of the vacuum chamber to the order of 1-10 Pa. At this time, the pressure is greater than the saturated vapor pressure of the solvent. In some embodiments, the first pressure is, for example, 6 Pa to 20 Pa.

[0091] S213: The pressure in the vacuum chamber is reduced from a first pressure to a second pressure using a molecular pump, wherein the second pressure is less than the saturated vapor pressure of the solvent.

[0092] In order to create a protective solvent saturated vapor pressure environment between the support plate and the condenser plate, it is necessary to use a molecular pump to further reduce the pressure in the vacuum chamber to a second pressure less than the solvent saturated vapor pressure, for example, 0.01 Pa to 1 Pa.

[0093] In some embodiments, Figure 7 for Figure 6 The detailed flowchart of step S212 is as follows: Figure 6 As shown, step S212: reducing the pressure in the vacuum chamber from atmospheric pressure to a first pressure using a dry pump, where the first pressure is greater than the saturated vapor pressure of the solvent, includes the following steps:

[0094] S2121: Low-speed pressure reduction operation, using a dry pump to rapidly reduce the pressure in the vacuum chamber from atmospheric pressure to a third pressure, for example, 1*10. 4 -5*10 4 Pa, also known as dry pump slow pumping, has a non-linear pumping rate to ensure that the pressure reduction is not too violent and to avoid the formation of airflow mura.

[0095] S2122: High-speed pressure reduction operation, which uses a dry pump to rapidly reduce the pressure in the vacuum chamber from the third pressure to the second pressure. It is also known as dry pump fast pumping. The fast pumping rate is also non-linear, ensuring that the first pressure is reached quickly.

[0096] In some embodiments, step S212: the use of a dry pump to reduce the pressure in the vacuum chamber from atmospheric pressure to a first pressure, the first pressure being greater than the saturated vapor pressure of the solvent, may also include a pressure stabilization operation, maintaining the pressure, for example, for a predetermined duration at a third pressure, and pre-drying the liquid under initial low pressure to ensure a stable film morphology, avoiding the violent activity of solvent molecules caused by high vacuum, which could lead to changes and deterioration of the film morphology.

[0097] The moment when the distance between the support plate and the condenser plate decreases to the first distance is during the low-speed depressurization operation. This facilitates quickly finding the moment when the space between the support plate and the condenser plate meets the saturated vapor pressure atmosphere during the subsequent rapid depressurization operation and the depressurization process using a molecular pump, thus facilitating subsequent precise control.

[0098] In some embodiments, step S22: performing the pressure stabilization drying stage operation, while maintaining the vacuum chamber at a first pressure state, gradually increasing the distance between the support plate and the condenser plate to a second distance includes the following steps:

[0099] After the space between the support plate and the condenser plate is at the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is continuously adjusted so that the distance between the support plate and the condenser plate increases from the first distance to the second distance.

[0100] In some embodiments, the distance between the support plate and the condenser plate may be increased starting at the moment when a captured solvent film appears on the condenser plate.

[0101] The adjustment can be done by uniform speed continuous adjustment or variable speed continuous adjustment. The adjustment rate should not be too fast to ensure that the space between the support plate and the condenser plate is basically in dynamic equilibrium of the saturated vapor pressure of the solvent during the adjustment process.

[0102] In some embodiments, step S22: performing the pressure stabilization drying stage operation, while maintaining the vacuum chamber at a first pressure state, gradually increasing the distance between the support plate and the condenser plate to a second distance includes the following steps:

[0103] After the space between the support plate and the condenser plate reaches the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is adjusted in stages so that the distance between the support plate and the condenser plate increases from a first distance to a second distance.

[0104] For example, the distance between the support plate and the condenser plate can be gradually adjusted in one or more stages to ensure that, during the adjustment process, the space between the support plate and the condenser plate is essentially in dynamic equilibrium with the saturated vapor pressure of the solvent.

[0105] Figure 8 The parameter curves of the low-temperature vacuum drying process for the OLED functional layer provided in the embodiments of this disclosure are shown.

[0106] like Figure 8 As shown, the vacuum drying (VCD) process includes stages such as slow pumping, pressure stabilization, fast pumping, molecular pump drying, and pressure boosting.

[0107] Specifically, the dry pump starts working after the carrier plate carries the film-forming substrate from the initial position toward the condenser plate. During the slow pumping operation, the carrier plate carries the film-forming substrate toward the condenser plate to the first position. At this time, the distance between the carrier plate and the condenser plate is the first distance and is maintained, for example, 14cm.

[0108] After the dry pump slowly pumps, stabilizes the pressure, and then pumps quickly, the pressure inside the vacuum chamber is stabilized below 1 Pa by the operation of the molecular pump, and a captured solvent film appears on the condenser plate at a time, for example, 600 s. This is when the carrier plate begins to control the film-forming substrate to move away from the condenser plate to a second distance, for example, 50 mm.

[0109] After the molecular pump drying process is complete, the vacuum chamber is restored to atmospheric pressure, for example, 10. 5 Pa, the carrier plate carries the film-forming substrate away from the condenser plate to the initial position.

[0110] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0111] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A vacuum drying film-forming apparatus, characterized in that, The vacuum drying film-forming device includes: A vacuum chamber configured to provide a variable pressure environment; The carrier plate is configured to support the substrate to be dried for film formation. A condenser plate is disposed above the support plate and parallel to the support plate, and is configured to condense and capture solvent evaporating from the film-forming substrate. The carrier plate is configured to move in a direction perpendicular to the condenser plate to adjust the distance between the carrier plate and the condenser plate. The pressure in the vacuum chamber and the distance between the carrier plate and the condenser plate are dynamically adjusted synchronously, so that during the drying process of the film layer on the film-forming substrate on the carrier plate, the space between the carrier plate and the condenser plate is basically always at the saturated vapor pressure of the solvent.

2. The vacuum drying film-forming apparatus according to claim 1, characterized in that, The vacuum drying film-forming apparatus further includes: A dry pump, connected to the vacuum chamber, configured to reduce the pressure in the vacuum chamber from atmospheric pressure to a first pressure greater than the saturated vapor pressure of the solvent; and A molecular pump, connected to the vacuum chamber, is configured to reduce the pressure in the vacuum chamber from a first pressure to a second pressure, the second pressure being lower than the saturated vapor pressure of the solvent.

3. The vacuum drying film-forming apparatus according to claim 1 or 2, characterized in that, The vacuum drying film-forming apparatus further includes a servo-driven linear actuator, which comprises: A support assembly extends through the bottom of the vacuum chamber and supports the bottom of the carrier plate. A drive motor drives the support link to move in a direction perpendicular to the condenser plate to adjust the distance between the support plate and the condenser plate.

4. The vacuum drying film-forming apparatus according to claim 1 or 2, characterized in that, At least one of the support plate and the condenser plate has an adjustable temperature.

5. A vacuum drying film formation method, characterized in that, The vacuum drying film formation method includes the following steps: The substrate to be dried and formed into a film is transferred to a carrier plate in a vacuum chamber; The pressure inside the vacuum chamber and the distance between the support plate and the condenser plate are dynamically adjusted synchronously so that the space between the support plate and the condenser plate is basically always at the saturated vapor pressure of the solvent evaporated from the film-forming substrate during the drying process of the film layer on the film-forming substrate. The dried film-forming substrate is transferred out of the vacuum chamber.

6. The vacuum drying film formation method according to claim 5, characterized in that, The synchronous dynamic adjustment of the pressure inside the vacuum chamber and the distance between the support plate and the condenser plate includes the following steps: The pressure reduction phase operation is performed, reducing the distance between the support plate and the condenser plate to a first distance, while simultaneously reducing the pressure of the vacuum chamber to a second pressure in stages; During the pressure stabilization and drying phase, while maintaining the vacuum chamber at the second pressure state, the distance between the support plate and the condenser plate is gradually increased to the second distance; and The pressurization phase is executed to restore the vacuum chamber pressure to atmospheric pressure and adjust the distance between the support plate and the condenser plate to the initial distance.

7. The vacuum drying film formation method according to claim 6, characterized in that, The pressure reduction phase operation, which reduces the distance between the support plate and the condenser plate to a first distance, and simultaneously reduces the pressure in the vacuum chamber to a second pressure in stages, includes the following steps: The distance between the support plate and the condenser plate is decreased at a constant speed, so that the distance between the support plate and the condenser plate is reduced from the initial distance to the first distance; A dry pump is used to reduce the pressure inside the vacuum chamber from atmospheric pressure to a first pressure, which is greater than the saturated vapor pressure of the solvent. A molecular pump is used to reduce the pressure in the vacuum chamber from a first pressure to a second pressure, where the second pressure is less than the saturated vapor pressure of the solvent.

8. The vacuum drying film formation method according to claim 7, characterized in that, The step of using a dry pump to reduce the pressure in the vacuum chamber from atmospheric pressure to a first pressure, where the first pressure is greater than the saturated vapor pressure of the solvent, includes the following steps: Low-speed depressurization operation: The pressure in the vacuum chamber is reduced from atmospheric pressure to a third pressure at a low speed using a dry pump. High-speed pressure reduction operation: The pressure in the vacuum chamber is rapidly reduced from the third pressure to the first pressure using a dry pump. The moment when the distance between the support plate and the condenser plate decreases to the first distance occurs during the low-speed depressurization operation.

9. The vacuum drying film formation method according to claim 6, characterized in that, The step of performing the pressure stabilization and drying stage, while maintaining the vacuum chamber at a first pressure state, involves gradually increasing the distance between the support plate and the condenser plate to a second distance, including the following steps: After the space between the support plate and the condenser plate is at the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is continuously adjusted so that the distance between the support plate and the condenser plate increases from the first distance to the second distance.

10. The vacuum drying film formation method according to claim 6, characterized in that, The step of performing the pressure stabilization and drying stage, while maintaining the vacuum chamber at a first pressure state, involves gradually increasing the distance between the support plate and the condenser plate to a second distance, including the following steps: After the space between the support plate and the condenser plate reaches the saturated vapor pressure of the solvent, the distance between the support plate and the condenser plate is adjusted in stages so that the distance between the support plate and the condenser plate increases from a first distance to a second distance.

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