Method and device for measuring evaporation parameters of liquid film in vacuum drying device

Abstract

The present disclosure describes a method and device for measuring the evaporation parameters of a liquid film in a vacuum drying device. The method includes establishing a gas model including a first equation and a second equation, wherein the first equation is a Bernoulli equation between a first section and a second section, and the second equation is an ideal gas state equation of the gas state at the first section and the second section; determining a first rate at the first section and related parameters related to the first rate based on the gas model; obtaining a total air volume when the receiving chamber does not contain a substrate and obtaining a second rate at the preset section based on the measured values ​​of related parameters at the preset section; obtaining an air residue at a preset moment when the receiving chamber contains a substrate and obtaining an extracted gas volume at the preset moment based on the second rate; and determining the evaporation parameters at the preset moment based on the extracted gas volume, the total air volume, and the air residue. Thus, the evaporation parameters of the liquid film can be measured during the vacuum drying device vacuuming process.

Description

Technical Field

[0001] The present disclosure generally relates to the field of vacuum drying technology, and more particularly to a method and device for measuring evaporation parameters of a liquid film used in a vacuum drying device. Background Art

[0002] Coating equipment is a device that can form a coating film (also called a coating) on ​​the surface of a substrate. It is commonly used in the fields of chip manufacturing, display manufacturing, solar cell manufacturing, or lithium battery manufacturing. Coating equipment forms a coating by coating a wet film on the surface of a substrate, and the wet film dries to form a coating.

[0003] Generally speaking, the wet film drying can be achieved by a vacuum dryer (Vacuum Dehydration, VCD). Specifically, after the wet film is coated on the substrate, the substrate to be dried is vacuumed by a vacuum dryer to evaporate the solvent and crystallize the solute. For example, in the preparation of a perovskite coating, the substrate coated with a perovskite precursor liquid film on the surface can be sent to a closed cavity of a VCD, and the closed cavity is vacuumed in a short time to crystallize the perovskite precursor liquid film. Therefore, in the vacuum treatment of VCD, factors related to the evaporation of the liquid film have a greater impact on the performance of the coating, especially in some fields that require higher performance accuracy of the coating, and more precise control of the evaporation of the liquid film is required.

[0004] However, in some industries, due to the long vacuuming time (for example, about 2 minutes), the performance requirements for the coating are relatively low. Based on experience, controlling the evaporation of the liquid film can basically meet the performance requirements of the coating. There is little research on the evaporation parameters of the liquid film, and there is an urgent need for a solution that can measure the evaporation parameters of the liquid film. Summary of the invention

[0005] The present disclosure is proposed in view of the above situation, and its purpose is to provide a method and device for measuring the evaporation parameters of a liquid film in a vacuum drying device, which can measure the evaporation parameters of the liquid film during the vacuum drying device performing a vacuum treatment.

[0006] To this end, a first aspect of the present disclosure provides a method for measuring the evaporation parameters of a liquid film for a vacuum drying device, wherein the vacuum drying device includes a receiving chamber that can receive a substrate coated with a liquid film and a vacuum device that is connected to the receiving chamber and forms a negative pressure in the receiving chamber by evacuating air. The measuring method includes: establishing a gas model, wherein the gas model includes a first equation and a second equation, wherein the first equation is a Bernoulli equation for the flow of a compressible gas between a first section located at an outlet of the vacuum device and a second section located in the vacuum drying device at a position other than the outlet, and the second equation is an ideal gas state equation for the gas state at the first section and the gas state at the second section. ; Determine the first rate at the first cross section based on the gas model, and then determine the relevant parameters related to the first rate; in the first state, obtain the total air volume in the vacuum drying device and obtain the second rate for the preset cross section based on the measured value of the relevant parameters at the preset cross section, the first state is the state that the accommodating chamber does not accommodate the substrate; at the preset moment of the second state, obtain the residual air volume in the vacuum drying device and obtain the extracted gas volume at the preset moment based on the second rate, the second state is the state that the accommodating chamber accommodates the substrate; and determine the evaporation parameter at the preset moment based on the extracted gas volume, the total air volume and the residual air volume. In this case, by determining the relevant parameters related to the first rate based on the gas model, and then determining the second rate based on the relevant parameters, the calculation of the evaporation rate of the vacuum drying device can be simplified to conveniently determine the evaporation rate of the vacuum drying device, which is conducive to the realization of the computing device. In addition, based on the relevant parameters related to the first rate, the evaporation parameters of the liquid film are determined by associating multiple parameters obtained in the no-load state and the liquid film state, which can improve the convenience of measuring the evaporation parameters of the liquid film and is conducive to the monitoring of the evaporation parameters.

[0007] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the vacuum drying device further includes a negative pressure tube, which is arranged between the accommodating chamber and the vacuum device and is used to connect the accommodating chamber and the vacuum device, the second cross section is located at the outlet of the accommodating chamber, and the first equation is:

[0008]

[0009] Among them, Z 1 represents the height of the first section from the ground, Z 2 represents the height of the second section from the ground, P 1 represents the first gas pressure at the first cross section, P 2 represents the second gas pressure at the second cross section, ρ 1represents the first gas density at the first cross section, ρ 2 represents the second gas density at the second cross section, v 1 represents the first gas flow rate at the first cross section, v 2 represents the second gas flow rate at the second cross section, ε 1 represents the first gas internal energy per unit mass at the first cross section, ε 2 represents the internal energy of the second gas per unit mass at the second cross section, H m represents the head of the vacuum device, h f represents the pipeline resistance of the negative pressure pipe, and g represents the acceleration due to gravity. Thus, the first equation for compressible ideal gas under isothermal conditions can be determined.

[0010] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the second equation is:

[0011] P 1 V 1 =nRT=P 2 V 2 ,

[0012] Among them, P 1 represents the first gas pressure, P 2 represents the second gas pressure, n represents the molar amount of gas flowing through the first cross section or the second cross section, R represents the gas constant, T represents the gas temperature at the first cross section or the second cross section, V 1 represents the first gas volume at the first cross section, V 2 represents the second gas volume at the second cross section. Thus, the second equation can be determined according to the gas conditions.

[0013] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, in determining the first rate based on the gas model, the relationship between the flow rate ratio and the pressure ratio between the first section and the second section is determined based on the second equation; the second gas flow rate is represented by the pressure ratio and the first gas flow rate based on the relationship; the first relationship between the first gas density and the first gas pressure and the gas temperature is determined based on the second equation, and the second relationship between the second gas density and the second gas pressure and the gas temperature is determined based on the second equation; the first gas flow rate is determined based on the second equation, the second gas flow rate, the first relationship and the second relationship; and the first gas flow rate is used as the first rate or the first gas flow rate is converted into a molar rate and used as the first rate. In this case, the variable parameters related to the first equation are represented by the gas pressure and the first gas flow rate through the second equation, and the first rate and the parameters related to the first rate are determined based on the first gas flow rate. Therefore, it is beneficial to determine the evaporation parameters of the liquid film based on the determined related parameters.

[0014] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the first rate is a molar rate, and the first rate satisfies the formula:

[0015]

[0016] Among them, N t1 represents the first rate, P 1 represents the first gas pressure, P 2 represents the second gas pressure, g represents the gravitational acceleration, R represents the gas constant, T represents the gas temperature, H m represents the lift, l represents the length of the negative pressure pipe, d represents the diameter of the negative pressure pipe, λ represents the resistance coefficient of the negative pressure pipe, and the related parameters are determined to be the first gas pressure and the second gas pressure based on the first rate. Thus, the first rate represented by the molar rate and the related parameters related to the first rate can be obtained.

[0017] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the relevant parameters are the first gas pressure at the first cross section and the second gas pressure at the second cross section. In the first state and after the start of the vacuuming, the gas pressure at the preset cross section at the first moment and the second moment greater than the first moment is measured to obtain the first measurement value and the second measurement value, and the first molar mass for the first measurement value and the second molar mass for the second measurement value are determined according to the ideal gas state equation, and the second rate is obtained based on the mass difference between the first molar mass and the second molar mass and the time difference between the second moment and the first moment. In this case, the evaporation rate of the vacuum drying device under the corresponding gas pressure can be obtained, and it is easy to calculate.

[0018] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, in the first state and before the start of air extraction, the gas pressure at the preset cross-section is measured and the total air volume is determined according to the ideal gas state equation.

[0019] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the residual air amount is determined based on the total pressure and the solvent partial pressure in the vacuum drying device at the preset moment.

[0020] In addition, in the measurement method involved in the first aspect of the present disclosure, optionally, the evaporation parameter is the evaporation amount of the liquid film and / or the evaporation rate of the liquid film at the preset moment, wherein the difference between the total air amount and the residual air amount is obtained, the difference is subtracted from the extracted gas amount to determine the evaporation amount, and the evaporation amount is divided by the preset moment to obtain the evaporation rate.

[0021] A second aspect of the present disclosure provides an apparatus for measuring evaporation parameters, including a pressure sensor and a computing device for receiving a measurement value of the pressure sensor and executing the measurement method involved in the first aspect of the present disclosure.

[0022] According to the present disclosure, a method and device for measuring evaporation parameters of a liquid film in a vacuum drying device are provided, which are capable of measuring the evaporation parameters of the liquid film during a vacuum drying device vacuuming process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings, in which:

[0024] Figure 1 is an exemplary schematic diagram showing a coating environment involved in the examples of the present disclosure.

[0025] Figure 2ADetailed description of the invention is given in detail below.

[0026] Figure 2B is an exemplary schematic diagram showing a vacuum drying device according to an example of the present disclosure.

[0027] Figure 3 Detailed description is a block diagram showing an exemplary measurement device according to an example of the present disclosure.

[0028] Figure 4 is an exemplary flow chart showing a measurement method involved in examples of the present disclosure.

[0029] Figure 5 is an exemplary flow chart showing the process of determining a first rate based on a gas model according to an example of the present disclosure.

[0030] Figure 6 FIG. 1 is an exemplary flowchart showing a method of obtaining a second speed at a preset cross section according to an example of the present disclosure.

[0031] Figure 7 is an exemplary flow chart showing an exemplary method of obtaining evaporation parameters after determining relevant parameters according to an example of the present disclosure. DETAILED DESCRIPTION

[0032] Hereinafter, with reference to the accompanying drawings, the preferred embodiments of the present disclosure are described in detail. In the following description, the same symbols are given to the same parts, and repeated descriptions are omitted. In addition, the accompanying drawings are only schematic diagrams, and the ratio of the sizes of the parts to each other or the shapes of the parts, etc. may be different from the actual ones. It should be noted that the terms "including" and "having" in the present disclosure and any variations thereof, such as the processes, methods, systems, products or devices of a series of steps or units included or possessed are not necessarily limited to those steps or units clearly listed, but may include or have other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. All methods described in the present disclosure may be performed in any suitable order, unless otherwise indicated herein or clearly contradictory to the context.

[0033] The examples disclosed herein relate to a method for measuring the evaporation parameters of a liquid film used in a vacuum drying device (which may also be referred to as a detection method or a determination method). The measurement method disclosed herein can be applied to the field of chip manufacturing, the field of display screen manufacturing, the field of solar cell manufacturing, or the field of lithium battery manufacturing. The measurement method disclosed herein can measure the evaporation parameters of the liquid film during the vacuum drying device's vacuum pumping process, and can then adjust the evaporation scheme of the liquid film based on the evaporation parameters. Thus, the performance indicators (such as density) of the coating can be more accurately controlled by monitoring the evaporation parameters of the liquid film. In addition, coatings of different thicknesses can be prepared by adjusting the evaporation parameters of the liquid film.

[0034] The measurement method involved in the examples of the present disclosure is particularly suitable for the preparation of very thin coatings. For example, it is used to prepare perovskite coatings in the field of perovskite solar cell preparation. The examples of the present disclosure will be described in detail below in conjunction with the accompanying drawings. Figure 1 is an exemplary schematic diagram showing a coating environment involved in the examples of the present disclosure.

[0035] refer to Figure 1 The coating environment may include a coating device 1, a vacuum drying device 2, and a heating stage 3. Taking the preparation of a perovskite coating in the coating environment as an example, by using the coating device 1 (e.g., Figure 1 The slit coating device shown in the figure) coats the perovskite precursor solution on the surface of the substrate 4; the substrate 4 with the perovskite precursor liquid film coated on the surface is sent to the closed chamber of the vacuum drying device 2, and the closed chamber is evacuated in a short time to extract the solvent, so that the perovskite precursor liquid film is quickly and evenly crystallized, and then moved to the heating table 3 for heating and crystal growth.

[0036] Figure 2A 2 is an exemplary block diagram showing a vacuum drying device 2 according to an example of the present disclosure. Figure 2B 1 is a schematic diagram showing an exemplary vacuum drying device 2 according to an example of the present disclosure.

[0037] In addition, refer to Figure 2A and Figure 2B In some examples, the vacuum drying device 2 (also referred to as vacuum drying equipment, vacuum dryer) may include a receiving chamber 21 and a vacuum device 22. The receiving chamber 21 may receive a substrate 4 coated with a liquid film. The vacuum device 22 may be a device that forms a negative pressure in the receiving chamber 21. For example, the vacuum device 22 may be a vacuum pump. In some examples, the vacuum device 22 may be in communication with the receiving chamber 21 and form a negative pressure in the receiving chamber 21 by exhausting air. Specifically, the vacuum device 22 may extract the volatile substances of the air and / or liquid film in the receiving chamber 21, so that the interior of the receiving chamber 21 becomes a negative pressure environment.

[0038] In addition, the pumping rate of the vacuum device 22 may be adjustable. In this case, when the measured evaporation parameters do not meet the requirements, the evaporation parameters can be controlled by adjusting the pumping rate, which is conducive to obtaining a coating with higher performance accuracy. For example, the perovskite precursor liquid film is about 3.3 microns thick, and the perovskite component inside is in an unsaturated state. When a certain amount of solvent evaporates, it enters a saturated state and begins to nucleate. Tiny dots (for example, dots of about 10 nanometers) can be seen under an electron microscope. These dots are generally evenly distributed. At this time, if the evaporation rate in the accommodating cavity 21 is too fast, the density of the coating may be too large (that is, too dense), otherwise it may cause the density of the coating to be too small (that is, too sparse). Therefore, the evaporation rate can be affected by adjusting the pumping rate, thereby achieving the purpose of more accurately controlling the density of the coating.

[0039] In some examples, continue to refer to Figure 2A and Figure 2B The vacuum drying device 2 may further include a negative pressure pipe 23. The negative pressure pipe 23 may be disposed between the accommodating chamber 21 and the vacuum device 22 and used to connect the accommodating chamber 21 and the vacuum device 22. In some examples, one end of the negative pressure pipe 23 may be connected to the accommodating chamber 21, and the other end may be connected to the vacuum device 22. In addition, the shape of the negative pressure pipe 23 is not particularly limited. Preferably, the shape of the negative pressure pipe 23 may be Figure 2B In other examples, the shape of the negative pressure tube 23 can also be a straight line or other various shapes. In some examples, the shape of the cross section at any point on the negative pressure tube 23 can be circular, elliptical or square.

[0040] In addition, since the maximum pressure of the vacuum drying device 2 is normal pressure (i.e., atmospheric pressure), the air compression factor can be 1 under normal pressure, so the gas in the vacuum drying device 2 can be regarded as an ideal gas in the measurement. Therefore, the ideal gas state equation can be used for modeling or calculation later.

[0041] In addition, the measuring device 5 (which may also be referred to as a measuring device or a measuring system, etc.) involved in the examples of the present disclosure may be used to implement the measuring method involved in the examples of the present disclosure. In some examples, the measuring device 5 may include a memory storing a program and a processor coupled to the memory. The processor may be configured to implement one or more steps in the measuring method involved in the examples of the present disclosure when the program in the memory is run by the processor.

[0042] Figure 3 is an exemplary block diagram showing a measuring device 5 according to an example of the present disclosure.

[0043] In some examples, reference Figure 3, the measuring device 5 may include a pressure sensor 51 and a computing device 52, and the computing device 52 is used to receive the measurement value of the pressure sensor 51 and perform one or more steps in the measurement method involved in the example of the present disclosure. In addition, the pressure sensor 51 (such as a pressure gauge) can be used to measure the pressure value (i.e., the measurement value) at the corresponding cross section in the vacuum drying device 2. The computing device 52 can be any device with computing capabilities. For example, the computing device 52 can be a cloud server, a personal computer, a mainframe, and a distributed computing system. In some examples, the pressure sensor 51 can communicate with the computing device 52 in a wired manner or a wireless manner. Preferably, a wireless method is adopted. As a result, the pressure sensor 51 can be easily arranged.

[0044] Figure 4 is an exemplary flow chart showing a measurement method involved in examples of the present disclosure.

[0045] In this embodiment, reference Figure 4 , the measurement method may include establishing a gas model (step S102), determining a first rate at a first cross section based on the gas model, and then determining relevant parameters related to the first rate (step S104), determining the total air volume and the second rate in the vacuum drying device 2 in the first state based on the relevant parameters (step S106), determining the residual air volume in the vacuum drying device 2 in the second state and the amount of extracted gas determined based on the second rate (step S108), and determining the evaporation parameters of the liquid film at a preset time based on the amount of extracted gas, the total air volume and the residual air volume (step S110). In this case, by determining relevant parameters related to the first rate based on the gas model, and then determining the second rate based on the relevant parameters, the calculation of the evaporation rate of the vacuum drying device 2 can be simplified to conveniently determine the evaporation rate of the vacuum drying device 2, which is beneficial to the implementation of the computing device 52. In addition, based on the relevant parameters related to the first rate, the evaporation parameters of the liquid film are determined by associating multiple parameters obtained in the no-load state and the liquid film state, which can improve the convenience of measuring the evaporation parameters of the liquid film and is beneficial to the monitoring of the evaporation parameters.

[0046] refer to Figure 4 In step S102, a gas model may be established. The gas model may include a first equation and a second equation. In this case, the first velocity at the outlet of the vacuum device 22 (i.e., the first velocity at the first cross section) can be determined by subsequent calculations using the first equation and the second equation in the gas model.

[0047] In addition, the first equation may be a Bernoulli equation. The first equation may be a Bernoulli equation for the flow of compressible gas between two cross sections of the vacuum drying device 2. Specifically, the first cross section may be located at the outlet of the vacuum device 22, and the second cross section may be located at a position other than the outlet of the vacuum device 22 in the vacuum drying device 2. Preferably, the second cross section may be located at the outlet of the accommodating chamber 21. That is, the first equation may be a Bernoulli equation for the flow of compressible gas between the first cross section located at the outlet of the vacuum device 22 and the second cross section located at the outlet of the accommodating chamber 21. In this case, the distance between the first cross section and the second cross section can be obtained more conveniently, which is conducive to improving the convenience of calculating the first rate.

[0048] As mentioned above, the vacuum drying device 2 may also include a negative pressure tube 23. For this purpose, the example disclosed herein also provides a first equation that comprehensively considers the negative pressure tube 23 and the second cross section is located at the outlet of the accommodating chamber 21. It should be noted that the first equation can be adjusted according to the situation to support the second cross section located at other positions. In addition, when the liquid film evaporates, the temperature of the liquid film can be equal to room temperature. When the pumping time is less than the preset time, it can be assumed that the pumping process is an isothermal process. Therefore, the first equation can be the Bernoulli equation for a compressible ideal gas under isothermal conditions. In addition, the preset time is not particularly limited in the present disclosure. When applied, it can be determined experimentally whether the pumping process can be assumed to be an isothermal process. For example, in the preparation of a thin film such as a perovskite coating, the pumping time is extremely short, and the pumping process can be assumed to be an isothermal process.

[0049] Specifically, the first equation can be expressed as formula (1):

[0050]

[0051] Among them, Z 1 It can represent the height of the first section from the ground, Z 2 It can represent the height of the second section from the ground, P 1 It can be expressed as the first gas pressure at the first cross section, P 2 The second gas pressure at the second cross section can be expressed as 1 The first gas density at the first cross section can be expressed as 2 The second gas density at the second cross section, v 1 It can represent the first gas flow rate at the first cross section, v 2 It can be expressed as the second gas flow rate at the second cross section, ε 1 It can be expressed as the first gas internal energy per unit mass at the first cross section, ε 2 The internal energy of the second gas per unit mass at the second cross section, H m It can represent the head of the vacuum device 22, hf can represent the pipeline resistance of the negative pressure pipe 23, and g can represent the acceleration due to gravity. Thus, the first equation for compressible ideal gas under isothermal conditions can be determined.

[0052] In addition, the second equation may be an ideal gas state equation. The second equation may be determined based on the gas conditions flowing through the first cross section and the second cross section. Specifically, the gas conditions may be that the amount of gas flowing through the first cross section and the second cross section is the same, the temperature is the same, and the pressure is different.

[0053] For the above-mentioned gas situation, according to the ideal gas state equation, the gas amount can be the gas molar amount, and the second equation can be expressed as formula (2):

[0054] P 1 V 1 =nRT=P 2 V 2 ,

[0055] Among them, P 1 It can represent the first gas pressure, P 2 can represent the second gas pressure, n can represent the molar amount of gas flowing through the first section or the second section, R can represent the gas constant, T can represent the gas temperature at the first section or the second section, V 1 It can represent the first gas volume at the first cross section, V 2 The second gas volume at the second cross section can be expressed. Thus, the second equation can be determined according to the gas conditions. In addition, R = 8.314 J / (mol.K).

[0056] Continue to refer Figure 4 In step S104, a first rate at the first cross section is determined based on the gas model, and then related parameters related to the first rate are determined. In addition, the first rate can also represent the evaporation rate of the vacuum drying device 2. In addition, the first rate can be represented by a flow rate or a molar rate.

[0057] The first equation and the second equation in the gas model are described above, and the first rate at the outlet of the vacuum device 22 can be determined by calculating the first equation and the second equation in the gas model. To this end, the example of the present disclosure also provides an exemplary process for determining the first rate based on the gas model (hereinafter referred to as the method for determining the first rate). Figure 5 is an exemplary flow chart showing the process of determining a first rate based on a gas model according to an example of the present disclosure.

[0058] Specifically, refer to Figure 5 , a method for determining the first rate may include:

[0059] Step S202: Determine the relationship between the flow rate ratio and the pressure ratio between the first section and the second section based on the second equation. In addition, the relationship between the flow rate ratio and the pressure ratio may be that the flow rate ratio between the first section and the second section is equal to the pressure ratio between the second section and the first section.

[0060] In some examples, the relationship between the volume ratio, pressure ratio, and flow rate ratio at the first cross section and the second cross section can be determined based on the second equation. Specifically, based on the above formula (2), the relationship between the volume ratio, flow rate ratio, and pressure ratio can satisfy formula (3):

[0061]

[0062] Among them, P 1 It can represent the first gas pressure, P 2 Can represent the second gas pressure, V 1 It can represent the first gas volume at the first cross section, V 2 The second gas volume at the second cross section, v 1 It can represent the first gas flow rate at the first cross section, v 2 A second gas flow rate at the second cross section may be represented.

[0063] Step S204: Based on the relationship between the flow rate ratio and the pressure ratio obtained in step S202, the second gas flow rate is expressed by using the pressure ratio and the first gas flow rate.

[0064] Taking the pressure ratio between the first cross section and the second cross section as an example, the second gas flow rate may be the product of the pressure ratio between the first cross section and the second cross section and the first gas flow rate. In this case, the second gas flow rate can be related only to the gas pressure and the first gas flow rate. Specifically, the second gas flow rate may be expressed as formula (4):

[0065]

[0066] Step S206: Determine a first relationship between the first gas density and the first gas pressure and the gas temperature based on the second equation. In some examples, the second equation may be multiplied by the molar molecular mass to obtain an equation including the gas mass, and then determine the gas density based on the gas mass and the gas volume. Specifically, the first gas density may be the gas mass divided by the first gas volume. Similarly, the following second gas density may be the gas mass divided by the second gas volume.

[0067] In addition, the second equation multiplied by the molar molecular mass can be expressed as equation (5):

[0068] M n P1 V 1 =M n nRT=mRT=M n P 2 V 2 ,

[0069] Among them, m can represent the gas mass, M n It can represent molar molecular mass.

[0070] The first relationship of the first gas density determined based on equation (5) can be expressed as equation (6):

[0071]

[0072] Among them, ρ 1 A first gas density may be represented.

[0073] Step S208: Determine a second relationship between the second gas density, the second gas pressure and the gas temperature based on the second equation. For details, see the description of step S206.

[0074] In addition, the second relationship of the second gas density determined based on equation (5) can be expressed as equation (7):

[0075]

[0076] Among them, ρ 2 The second gas density may be represented by .

[0077] Step S210: Determine the first gas flow rate based on the second equation, the second gas flow rate, the first relationship and the second relationship.

[0078] In some examples, the heights of the first cross section and the second cross section from the ground in the second equation may be set to 0. That is, the change in the height from the ground may be ignored.

[0079] In addition, the pipeline resistance of the negative pressure tube 23 can be determined by the second gas flow rate. In this case, when the second gas flow rate is only related to the gas pressure and the first gas flow rate, the pipeline resistance can also be only related to the gas pressure and the first gas flow rate.

[0080] Taking the negative pressure pipe 23 having a diameter as an example, the pipe resistance of the negative pressure pipe 23 can be expressed as formula (8):

[0081]

[0082] Wherein, l may represent the length of the negative pressure tube 23, d may represent the diameter of the negative pressure tube 23, and λ may represent the resistance coefficient of the negative pressure tube 23. It should be noted that the representation of the pipeline resistance of the negative pressure tube 23 can be replaced with a representation related to the flow rate of the second gas according to the shape of the cross section of the negative pressure tube 23, and the present disclosure does not impose any particular restrictions on the pipeline resistance of the negative pressure tube 23. In addition, λ is related to the wall surface of the negative pressure tube 23, the elbow, and the gas flow mode.

[0083] Therefore, taking the negative pressure tube 23 with a diameter as an example, the first gas flow rate can be determined by substituting the second gas flow rate represented by the pressure ratio and the first gas flow rate, the first relationship and the second relationship into the second equation (i.e., equation (1)) for calculation.

[0084] Specifically, after substituting the above parameters and relational expressions into the second equation, equation (9) can be obtained:

[0085]

[0086] According to the fact that the gas temperature in the vacuum drying device 2 is the same as the gas temperature at the outlet of the vacuum device 22, it is determined that the internal energy of the first gas is the same as the internal energy of the second gas, that is, ε 1 =ε 2 , further simplifying formula (9) to formula (10):

[0087]

[0088] The first gas flow rate finally obtained can be expressed as formula (11):

[0089]

[0090] Step S212: using the first gas flow rate as the first rate or converting the first gas flow rate into a molar rate and using it as the first rate. Specifically, it can be selected whether to convert the first gas flow rate into a molar rate as required.

[0091] Taking the first rate as the molar rate as an example, the first rate can satisfy equation (12):

[0092]

[0093] Among them, N t1 It can represent the first rate, P 1 It can represent the first gas pressure, P 2 can represent the second gas pressure, g can represent the acceleration of gravity, R can represent the gas constant, T can represent the gas temperature, H mmay represent the lift, l may represent the length of the negative pressure pipe 23, d may represent the diameter of the negative pressure pipe 23, and λ may represent the resistance coefficient of the negative pressure pipe 23. Thus, the first rate represented by the molar rate and related parameters related to the first rate can be obtained.

[0094] In the above determination of the first rate based on the gas model, the variable parameters related to the first equation are expressed by the gas pressure and the first gas flow rate through the second equation, and the first rate and the parameters related to the first rate are determined based on the first gas flow rate. Therefore, the determination of the evaporation parameters of the liquid film based on the determined related parameters is beneficial.

[0095] As described above, in step S104, relevant parameters related to the first rate may also be determined. Specifically, the relevant parameters may be variables that affect the first rate. In some examples, the relevant parameters related to the first rate (that is, the relevant parameters related to the evaporation rate of the vacuum drying device 2) may be determined from equation (11) corresponding to the first gas flow rate or equation (12) corresponding to the first rate. Taking equation (12) corresponding to the first rate as an example, H m It is related to the rotation speed and structure of the vacuum device 22 itself and is a constant value. At the same time, it is assumed that λ is also a constant value. Therefore, the first rate and P are determined. 1 (first gas pressure) and P 2 (second gas pressure). That is, based on the first rate, the relevant parameters can be determined to be the first gas pressure and the second gas pressure. In other words, the relevant parameter related to the first rate can be the gas pressure.

[0096] Return to reference Figure 4 In step S106, the total air volume and the second rate in the vacuum drying device 2 in the first state are determined based on the relevant parameters. In addition, the first state can be a state where the accommodating chamber 21 does not accommodate the substrate 4.

[0097] As described above, the relevant parameter related to the first rate may be the gas pressure, and the second rate may be determined based on the gas pressure. That is, the second rate may also represent the evaporation rate of the vacuum drying device 2. In this case, the calculation method of the evaporation rate of the vacuum drying device 2 may be simplified based on the relevant parameters. Thus, the execution of the computing device 52 may be facilitated and the computing efficiency may be improved.

[0098] In addition, the total air volume can be the amount of air in the vacuum drying device 2 when the accommodating chamber 21 does not contain the substrate 4. In some examples, the gas pressure at the preset cross section can be measured in the first state and before the start of the vacuum pumping (i.e., under normal pressure) and the total air volume can be determined according to the ideal gas state equation. In addition, the total air volume can be expressed by molar mass. Specifically, the total air volume can be expressed as formula (13):

[0099]

[0100] Among them, N 0 Can represent the total air volume, P a0 It can represent the gas pressure at the preset cross section before the start of the vacuum pumping, V can represent the volume of the vacuum drying device 2, R can represent the gas constant, T a It can represent the gas temperature at the preset cross section. In addition, the volume of the vacuum drying device 2 can be a constant value. In addition, R and T appearing below a It can express the same meaning as V, so I will not repeat it.

[0101] In some examples, in the first state, the total amount of air in the vacuum drying device 2 can be obtained and the second rate at the preset cross section can be obtained based on the measured values ​​of the relevant parameters at the preset cross section. For the second rate, taking the relevant parameter as gas pressure as an example, the pressure sensor 51 can be set at the preset cross section in the vacuum drying device 2, and after the first state and the start of the vacuum pumping, the gas pressure at multiple moments at the preset cross section is measured to obtain multiple measurement values, and then the second rate at the preset cross section is obtained based on the multiple measurement values. In other words, based on the determined relevant parameters, the second rate at the preset cross section can be obtained by the gas pressure and time data obtained when the vacuum drying device 2 has no liquid film. In this case, the second rate can be easily determined and the second rate can be easily calculated by the computing device 52, which is conducive to the subsequent determination of the evaporation parameters of the liquid film.

[0102] Figure 6 FIG. 1 is an exemplary flowchart showing a method of obtaining a second speed at a preset cross section according to an example of the present disclosure.

[0103] Taking two moments and the gas mass expressed in molar mass as an example, it should be noted that if the gas mass is expressed in other units, the corresponding substitution can be made without restriction, see Figure 6 , obtaining a second rate at a preset cross section may include:

[0104] Step S302: in the first state and after the start of the gas extraction, respectively measure the gas pressure at a preset cross section at a first moment and a second moment greater than the first moment to obtain a first measurement value and a second measurement value.

[0105] Step S304: Determine a first molar mass for the first measured value and a second molar mass for the second measured value according to the ideal gas state equation. Specifically, the first molar mass can be expressed as formula (14):

[0106]

[0107] Among them, n 1Can represent the first molar mass, P a1 A first measurement value may be represented.

[0108] In addition, the second molar mass can be expressed as formula (15):

[0109]

[0110] Among them, n 2 Can represent the second molar mass, P a2 A second measurement value may be represented.

[0111] Step S306: Obtain a second rate based on the mass difference between the first molar mass and the second molar mass and the time difference between the second moment and the first moment. In some examples, the mass difference may be divided by the time difference to obtain the second rate. Specifically, the second rate may be expressed as formula (16):

[0112]

[0113] Among them, N t2 The second rate, P a1 The first measurement value, P a2 The second measurement value, t 1 It can represent the first moment, t 2 In this case, the evaporation rate of the vacuum drying device 2 under the corresponding gas pressure can be obtained, and it is easy to calculate. That is, the relevant parameters determined by the above steps can simplify the calculation method of the evaporation rate of the vacuum drying device 2.

[0114] Return to reference Figure 4 In step S108, the amount of residual air in the vacuum drying device 2 in the second state and the amount of extracted gas determined based on the second rate are determined. In addition, the second state may be a state in which the accommodating chamber 21 accommodates the substrate 4.

[0115] Specifically, in step S108, at a preset time in the second state, the residual amount of air in the vacuum drying device 2 can be obtained, and the amount of extracted gas at the preset time can be obtained based on the second rate.

[0116] In addition, the residual air amount may be the amount of air in the vacuum drying device 2 at a preset time when the accommodating chamber 21 accommodates the substrate 4. In some examples, the residual air amount may be determined based on the total pressure and the solvent partial pressure in the vacuum drying device 2 at the preset time. In some examples, the residual air amount may be expressed in molar terms as in formula (17):

[0117]

[0118] Among them, N a Can indicate the residual air volume, P t It can represent the total pressure in the vacuum drying device 2 at a preset time, P S It can represent the solvent partial pressure.

[0119] In addition, the amount of gas extracted can be the total amount of gas extracted by the vacuum device 22. Since the evaporation rate of the vacuum drying device 2 is determined to be only related to the gas pressure based on the first rate, the second rate obtained using the no-load condition without a liquid film (i.e., the first state) is also applicable to the condition with a liquid film (i.e., the second state). Specifically, the amount of gas extracted can be obtained by performing a double integration of the gas pressure and time on the second rate. In some examples, the amount of gas extracted can be expressed in molar terms as formula (18):

[0120] N = ∫∫N t2 dt dp,

[0121] Among them, N can represent the amount of gas extracted, N t2 may represent the second rate, t may represent time, and p may represent gas pressure.

[0122] Continue to refer Figure 4 In step S110, the evaporation parameters of the liquid film at a preset time are determined based on the extracted gas volume, the total air volume and the residual air volume.

[0123] In some examples, the evaporation parameter may be the evaporation amount of the liquid film and / or the evaporation rate of the liquid film at a preset time.

[0124] In some examples, the difference between the total air volume and the residual air volume can be obtained, and the difference can be subtracted from the extracted gas volume to determine the evaporation amount of the liquid film. Thus, the evaporation amount of the liquid film can be determined. In some examples, the evaporation amount of the liquid film can be expressed in molar terms as formula (19):

[0125] N s =N-(N 0 -N a ),

[0126] Among them, N s It can represent the evaporation amount of liquid film, N can represent the amount of extracted gas, N 0 Can represent the total air volume, N a Can indicate the amount of residual air.

[0127] In some examples, the evaporation amount of the liquid film may be divided by a preset time to obtain the evaporation rate of the liquid film, thereby determining the evaporation rate of the liquid film.

[0128] In some examples, the measurement method may further include obtaining evaporation parameters corresponding to multiple preset cross sections at a preset time, and averaging them to determine the target evaporation parameters. Thus, the evaporation parameters can be made more accurate. For example, the evaporation amount of the liquid film corresponding to multiple preset cross sections at a preset time may be averaged, and / or the evaporation rate of the liquid film corresponding to multiple preset cross sections at a preset time may be averaged.

[0129] Figure 7 is an exemplary flow chart showing an exemplary method of obtaining evaporation parameters after determining relevant parameters according to an example of the present disclosure.

[0130] As mentioned above, the evaporation parameters of the liquid film at a preset time can be determined based on multiple parameters in the first state and the second state. To this end, the present disclosure also provides a more specific embodiment. Specifically, refer to Figure 7 , the embodiment may include:

[0131] Step S402, setting a first pressure sensor and a second pressure sensor. Specifically, the first pressure sensor can be set at a preset cross section of the vacuum drying device 2, and the second pressure sensor can be set at a position in the vacuum drying device 2 where the total pressure can be obtained.

[0132] Step S404, when there is no liquid film in the vacuum drying device 2, obtaining an initial measurement value collected by the first pressure sensor before the start of vacuuming, and obtaining a first measurement value collected by the first pressure sensor at the first moment and a second measurement value collected at the second moment after the start of vacuuming.

[0133] Step S406, obtaining the total air volume, the first molar mass, and the second molar mass corresponding to the initial measurement value, the first measurement value, and the second measurement value, respectively, according to the ideal gas state equation.

[0134] Step S408: Obtaining a second rate based on the mass difference between the first molar mass and the second molar mass and the time difference between the second moment and the first moment.

[0135] Step S410, when there is a liquid film in the vacuum drying device 2, the total pressure collected by the second pressure sensor is obtained at a preset time after the start of vacuuming, the residual air amount is obtained based on the ideal gas state equation and the total pressure and the solvent partial pressure, and the amount of extracted gas at the preset time is determined based on the second rate.

[0136] Step S412, determining the evaporation parameters of the liquid film at a preset time based on the extracted gas volume, the total air volume and the residual air volume.

[0137] The present disclosure also relates to an electronic device, which may include at least one processing circuit. The at least one processing circuit is configured to perform one or more steps in the above-mentioned measurement method.

[0138] The present disclosure also relates to a computer-readable storage medium, which may store at least one instruction, and when the at least one instruction is executed by a processor, one or more steps in the above-mentioned measurement method are implemented.

[0139] Although the present disclosure is specifically described above in conjunction with the accompanying drawings and examples, it is to be understood that the above description does not limit the present disclosure in any form. Those skilled in the art may modify and change the present disclosure as needed without departing from the essential spirit and scope of the present disclosure, and these modifications and changes all fall within the scope of the present disclosure.

Claims

1. A method for measuring evaporation parameters of a liquid film in a vacuum drying device, wherein the vacuum drying device comprises a receiving chamber for receiving a substrate coated with a liquid film and a vacuum device connected to the receiving chamber and forming a negative pressure in the receiving chamber by exhausting air, characterized in that: The measurement method comprises: establishing a gas model, wherein the gas model comprises a first equation and a second equation, wherein the first equation is a Bernoulli equation for compressible gas flow between a first section located at the outlet of the vacuum device and a second section located in the vacuum drying device at a position other than the outlet, and the second equation is an ideal gas state equation for the gas state at the first section and the gas state at the second section; determining a first velocity at the first section based on the gas model, and then determining relevant parameters related to the first velocity; in a first state, obtaining a total air volume in the vacuum drying device and obtaining a second velocity at the preset section based on the measured values ​​of the relevant parameters at a preset section, wherein the first state is a state in which the accommodating chamber does not accommodate the substrate; at a preset time of the second state, obtaining a residual air volume in the vacuum drying device and obtaining a gas volume extracted at the preset time based on the second velocity, wherein the second state is a state in which the accommodating chamber accommodates the substrate; and determining an evaporation parameter at the preset time based on the extracted gas volume, the total air volume and the residual air volume, wherein The relevant parameters are the first gas pressure at the first cross section and the second gas pressure at the second cross section. In the first state and after the start of the vacuuming, the gas pressure at the preset cross section at the first moment and the second moment greater than the first moment is measured respectively to obtain the first measurement value and the second measurement value. The first molar mass for the first measurement value and the second molar mass for the second measurement value are determined according to the ideal gas state equation. The second rate is obtained based on the mass difference between the first molar mass and the second molar mass and the time difference between the second moment and the first moment. In the first state and before the start of the vacuuming, the gas pressure at the preset cross section is measured and the total air volume is determined according to the ideal gas state equation. The residual air volume is determined based on the total pressure and the solvent partial pressure in the vacuum drying device at the preset moment. The evaporation parameter is the evaporation volume of the liquid film and / or the evaporation rate of the liquid film at the preset moment. The difference between the total air volume and the residual air volume is obtained, the difference is subtracted from the extracted gas volume to determine the evaporation volume, and the evaporation volume is divided by the preset moment to obtain the evaporation rate.

2. The measuring method according to claim 1, characterized in that: The vacuum drying device further includes a negative pressure pipe, which is disposed between the accommodating chamber and the vacuum device and is used to connect the accommodating chamber and the vacuum device. The second cross section is located at the outlet of the accommodating chamber. The first equation is: in, represents the height of the first section from the ground, represents the height of the second section from the ground, represents the first gas pressure at the first cross section, represents the second gas pressure at the second cross section ， represents the first gas density at the first cross section, represents the second gas density at the second cross section, represents the first gas flow rate at the first cross section, represents the second gas flow rate at the second cross section, represents the first gas internal energy per unit mass at the first cross section, represents the second gas internal energy per unit mass at the second cross section, represents the head of the vacuum device, represents the pipe resistance of the negative pressure pipe, Represents the acceleration due to gravity.

3. The measuring method according to claim 2, characterized in that: The second equation is: ， in, represents the first gas pressure, represents the second gas pressure, represents the molar amount of gas flowing through the first cross section or the second cross section, is the gas constant, represents the gas temperature at the first cross section or the second cross section, represents the first gas volume at the first cross section, represents the second gas volume at the second cross section.

4. The measuring method according to claim 3, characterized in that: In determining the first rate based on the gas model, determining a relationship between a flow rate ratio and a pressure ratio between the first cross section and the second cross section based on the second equation; expressing the second gas flow rate using the pressure ratio and the first gas flow rate based on the relationship; Determine a first relationship between the first gas density and the first gas pressure and the gas temperature based on the second equation, and determine a second relationship between the second gas density and the second gas pressure and the gas temperature based on the second equation; determining the first gas flow rate based on the second equation, the second gas flow rate, the first relationship, and the second relationship; and The first gas flow rate is taken as the first rate or the first gas flow rate is converted into a molar rate and taken as the first rate.

5. The measuring method according to claim 3, characterized in that: The first rate is a molar rate, and the first rate satisfies the formula: in, represents the first rate, represents the first gas pressure, represents the second gas pressure, represents the gravitational acceleration, represents the gas constant, represents the gas temperature, represents the lift, represents the length of the negative pressure tube, represents the diameter of the negative pressure tube, represents the resistance coefficient of the negative pressure tube, The related parameters are determined to be the first gas pressure and the second gas pressure based on the first rate.

6. A device for measuring evaporation parameters, characterized in that: The invention comprises a pressure sensor and a computing device for receiving a measurement value of the pressure sensor and executing the measurement method according to any one of claims 1 to 5.

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