Liquid supply device and coating device

Abstract

To provide a technique capable of accurately measuring the residual amount of liquid with the high viscosity in a tank at a low cost.SOLUTION: A liquid supply unit 10 comprises: a deaeration tank 13; a first liquid supply pipe 12 which supplies varnish into the deaeration tank 13; and a second liquid supply pipe 14 which discharges the varnish to the outside of the deaeration tank 13. The liquid supply unit 10 comprises: a first flow sensor 41 which detects the flow amount of the varnish passing inside the first liquid supply pipe 12 on the outside of the first liquid supply pipe 12; a second flow sensor 42 which detects the flow amount of the varnish passing inside the second liquid supply pipe 14 on the outside of the second liquid supply pipe 14; and a control unit 30 which calculates the residual amount of the varnish in the deaeration tank 13 on the basis of the output of the first flow sensor 41 and the output of the second flow sensor 42.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The subject matter disclosed herein relates to fluid dispensing devices and applicator devices. [Background technology]

[0002] Conventionally, in the manufacturing process of precision electronic device substrates such as glass substrates for liquid crystal displays, semiconductor substrates, glass substrates for PDPs, glass substrates for photomasks, substrates for color filters, substrates for recording disks, substrates for solar cells, substrates for electronic paper, rectangular glass substrates, flexible substrates for film liquid crystals, and substrates for organic EL (hereinafter simply referred to as "substrates"), a coating device that coats the surface of a substrate with a liquid such as photoresist has been used. A conventional coating device is described, for example, in Patent Document 1. The coating device of Patent Document 1 discharges a coating liquid from a slit die having a slit-shaped discharge port onto a substrate held by suction on a stage that is movable horizontally. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-23990 Summary of the Invention [Problem to be solved by the invention]

[0004] When measuring the amount of liquid remaining in a tank, a level sensor that measures the liquid level may be used. Known level sensors include capacitance type, ultrasonic reflection type, laser reflection type, optical reflection type, float type, vibration type, electrode type, and paddle type.

[0005] However, when the liquid has high viscosity (for example, 1000 cp to 10000 cp), it is difficult to measure the liquid level using the above-mentioned level sensors. For example, when the liquid is highly viscous, bubbles tend to form on the liquid surface, preventing the liquid level from remaining horizontal, making it difficult to obtain accurate measurements using a reflection-type level sensor. Furthermore, when using float-type, electrode-type, or paddle-type level sensors, the highly viscous liquid may stick to the sensor, causing the sensor to malfunction. Furthermore, when using capacitance-type sensors, the range of application is limited, as it is difficult to use them with liquids containing flammable organic solvents.

[0006] Another method involves installing a weighing scale at the bottom of the tank and calculating the remaining amount of liquid from the reading. However, in the case of a sturdy tank, such as a pressurized tank, the weight of the tank itself is significantly greater than the weight of the liquid stored inside. This makes it difficult to accurately measure the remaining amount of processing liquid in the tank using a weighing scale capable of measuring large weights. For example, if 50 kg of liquid is placed in a tank weighing 250 kg, the total weight will be 300 kg. If a weighing scale with a full scale of 500 kg and an accuracy of 0.1% is used, the measurement error will be 0.5 kg, which means that the accuracy for 50 kg of liquid will be reduced to about 1%. Furthermore, highly accurate weighing scales are expensive, which increases the cost of the equipment.

[0007] An object of the present invention is to provide a technique that can measure the remaining amount of a highly viscous liquid in a tank with high accuracy and at low cost. [Means for solving the problem]

[0008] In order to solve the above problems, a first aspect is a liquid supply device that supplies a processing liquid, the liquid supply device including: a tank capable of storing a highly viscous processing liquid; a supply pipe that supplies the processing liquid into the tank; a discharge pipe that discharges the processing liquid out of the tank; a first flow rate sensor that detects the flow rate of the processing liquid passing through the supply pipe outside the supply pipe; a second flow rate sensor that detects the flow rate of the processing liquid passing through the discharge pipe outside the discharge pipe; and a calculation unit that calculates the remaining amount of the processing liquid in the tank based on an output of the first flow rate sensor and an output of the second flow rate sensor. The first flow rate sensor or the second flow rate sensor is a non-contact type flow rate sensor that does not come into contact with the processing liquid in the supply pipe. .

[0009] A second aspect is a liquid supply device of the first aspect, further comprising a pressure reducing section that reduces the pressure inside the tank, an exhaust pipe that discharges gas outside the tank, and a third flow sensor that detects the flow rate of the gas passing through the exhaust pipe, and the calculation section calculates the remaining amount of the processing liquid in the tank based on the output of the third flow sensor.

[0010] A third aspect is the liquid supply device of the first or second aspect, further comprising a pressurizing unit that pressurizes the inside of the tank.

[0011] A fourth aspect is the liquid supply device of the first or third aspect, wherein the viscosity of the treatment liquid is 1000 cP or more and 10000 cP or less. A fifth aspect is a liquid supply device according to any one of the first to fourth aspects, wherein the non-contact flow sensor is an ultrasonic or laser sensor that outputs ultrasonic or laser light irradiation waves from an output section toward a pipe, and detects the frequency change of the reflected waves that are reflected when the irradiation waves hit particles in the pipe using a detection section.

[0012] No. 6 The embodiment is a coating device, which is any of the first to third embodiments. 5 The apparatus includes the liquid supply device according to any one of the aspects and a nozzle that discharges the processing liquid supplied from the liquid supply device. [Effects of the Invention]

[0013] According to the liquid supply device of the first aspect, the amount of treatment liquid supplied into the tank can be measured by the first flow rate sensor, and the amount of treatment liquid discharged out of the tank can be measured by the second flow rate sensor, so that the remaining amount of treatment liquid in the tank can be accurately calculated based on the outputs of the first flow rate sensor and the second flow rate sensor.

[0014] According to the liquid supply device of the second aspect, the evaporation amount of the processing liquid contained in the gas passing through the exhaust pipe can be obtained based on the output of the third flow sensor, and therefore the remaining amount of the processing liquid in the tank can be calculated more accurately based on the output of the third flow sensor.

[0015] According to the liquid supply device of the third aspect, by pressurizing the inside of the tank, it is possible to supply a highly viscous processing liquid to a supply destination.

[0016] According to the liquid supply device of the fourth aspect, the remaining amount of treatment liquid having a viscosity of 1000 cP or more and 10000 cP or less can be calculated.

[0017] No. 6 According to the application device of this aspect, a highly viscous treatment liquid can be applied to an object. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram showing a configuration of a coating apparatus according to an embodiment. [Figure 2] FIG. 2 is a perspective view of the application unit shown in FIG. [Figure 3] FIG. 2 is a block diagram showing connections between a control unit and each unit in the coating apparatus. [Figure 4] FIG. 2 is a diagram schematically illustrating the degassing tank in a state in which varnish is being discharged. [Figure 5] FIG. 10 is a diagram showing a degassing tank according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the components described in the embodiment are merely examples and are not intended to limit the scope of the present invention. In the drawings, the dimensions and numbers of each part may be exaggerated or simplified as necessary to facilitate understanding.

[0020] <1. Embodiment> FIG. 1 is a diagram showing the configuration of a coating apparatus 1 according to an embodiment. The coating apparatus 1 is applied, for example, to a manufacturing process of a polyimide film that serves as a base material for a flexible display. In the manufacturing process of the polyimide film, the coating apparatus 1 applies a varnish, which is a high-viscosity processing liquid containing a polyimide precursor (polyamic acid), to the upper surface of a glass carrier substrate 9. Thereafter, in an apparatus separate from the coating apparatus 1, the varnish on the carrier substrate 9 is subjected to processes such as heating, decompression, and baking.

[0021] 1, the coating apparatus 1 includes a liquid supply unit 10 (liquid supply device), a coating unit 20, and a control unit 30. Each component of the coating apparatus 1 will be described below.

[0022] <Liquid supply unit> The liquid supply unit 10 is an apparatus that supplies a highly viscous processing liquid to a coating unit 20, which is a supply destination. The liquid supply unit 10 has a supply tank 11, a first liquid supply pipe 12, a degassing tank 13, a second liquid supply pipe 14, a pressurizing mechanism 15, and a decompression mechanism 16.

[0023] The supply tank 11 is a container for storing varnish before supply. The varnish stored in the supply tank 11 may be unused or may be recycled varnish that has been used once. As described above, varnish is a highly viscous treatment liquid. The viscosity of varnish is, for example, approximately 1000 to 10,000 cP (1 to 10 Pa·s). In the following description, "high viscosity" refers to a viscosity of 1000 cP (1 Pa·s) or higher. Note that the highly viscous treatment liquid supplied by the liquid supply unit 10 is not limited to varnish containing a polyimide precursor, but may also be a highly viscous treatment liquid other than varnish. In the following description, the side closer to the supply tank 11 is referred to as the upstream side, and the side opposite the supply tank 11 is referred to as the downstream side.

[0024] The liquid supply unit 10 has one supply tank 11, but may have multiple supply tanks 11. In this case, the multiple supply tanks 11 may be switchably connected to the first liquid supply pipe 12.

[0025] The first liquid supply pipe 12 is a pipe connecting the supply tank 11 and the degassing tank 13. The upstream end of the first liquid supply pipe 12 is connected to the supply tank 11. The downstream end of the first liquid supply pipe 12 is connected to the degassing tank 13. A first liquid supply valve V11 and a first filter F1 are provided on the path of the first liquid supply pipe 12. When the first liquid supply valve V11 and a first pressurization valve V21 (described later) are opened, the varnish in the supply tank 11 is sent to the degassing tank 13 through the first liquid supply pipe 12 by the pressure of the gas supplied from the pressurization mechanism 15. At this time, the varnish is filtered by the first filter F1. As a result, fine dust contained in the varnish is captured and removed by the first filter F1.

[0026] 1, the liquid supply unit 10 has one first filter F1. However, the liquid supply unit 10 may have multiple first filters F1. In that case, it is sufficient that the multiple first filters F1 are connected in parallel on the path of the first liquid supply pipe 12.

[0027] The degassing tank 13 is a container for reducing the amount of gas dissolved in the varnish. A pressure reduction mechanism 16, which will be described later, is connected to the degassing tank 13. When the pressure reduction valve V23 of the pressure reduction mechanism 16 is opened and the pressure reduction pump 162 is operated, the internal space of the degassing tank 13 is reduced in pressure, and the air pressure inside the degassing tank 13 becomes a negative pressure lower than atmospheric pressure. As a result, the dissolved gas contained in the varnish inside the degassing tank 13 becomes bubbles. Also, an agitation mechanism 131 is provided inside the degassing tank 13. When the agitation mechanism 131 is rotated, the varnish inside the degassing tank 13 is agitated, and the air bubbles in the varnish rise to the surface of the varnish. After rising, the bubbles are removed by being sucked from the degassing tank 13 into the pressure reduction mechanism 16. This reduces the amount of gas dissolved in the varnish.

[0028] In this way, in the coating apparatus 1 of this embodiment, dissolved gases contained in the varnish are removed in advance before coating, which makes it possible to prevent air bubbles from being generated in the varnish when the varnish coated on the carrier substrate 9 is heated and baked in a subsequent process.

[0029] 1, the liquid supply unit 10 has one degassing tank 13. However, the liquid supply unit 10 may have a plurality of degassing tanks 13. In this case, the plurality of degassing tanks 13 may be switchably connected between the first liquid supply pipe 12 and the second liquid supply pipe 14.

[0030] The second liquid supply pipe 14 is a pipe that connects the degassing tank 13 and the coating unit 20. An upstream end of the second liquid supply pipe 14 is connected to a lower part of the degassing tank 13. A downstream end of the second liquid supply pipe 14 is connected to a third liquid supply pipe 23 of the coating unit 20. In addition, a second liquid supply valve V12, a second filter F2, and an assist pump P1 are arranged in the second liquid supply pipe 14.

[0031] When the pressure reducing valve V23 is closed and the second liquid supply valve V12 and the second pressurizing valve V22 (described later) are opened, the varnish in the degassing tank 13 is sent through the second liquid supply pipe 14 to the slit nozzle 22 of the coating unit 20 by the pressure of the gas supplied from the pressurizing mechanism 15. The pressurizing mechanism 15 is an example of a liquid sending section that sends the highly viscous processing liquid from the supply tank 11 toward the liquid supply port 19. In addition, the force of sending the varnish is assisted by driving the assist pump P1. The assist pump P1 is an example of a liquid sending pump.

[0032] The assist pump P1 may be, for example, a constant-volume pump that discharges a constant amount of liquid per discharge. In this case, the amount of varnish that the assist pump P1 delivers per discharge may be the same as the amount of varnish that the slit nozzle 22 applies to one carrier substrate 9. The assist pump P1 is preferably a so-called tube-phragm pump that discharges the processing liquid from a tube by applying fluid pressure to the outer surface of a contractible tube. By employing a tube-phragm pump, generation of particles in the assist pump P1 due to the discharge of varnish can be suppressed.

[0033] The second filter F2 has a smaller pore size (finer mesh) than the first filter F1. The varnish flowing through the second liquid supply pipe 14 is filtered by the second filter F2. As a result, fine dust particles contained in the varnish are captured and removed by the second filter F2.

[0034] The liquid supply unit 10 includes one second filter F2, but may include multiple second filters F2. In this case, the multiple second filters F2 may be connected in parallel on the path of the second liquid supply pipe 14.

[0035] The pressurizing mechanism 15 is a mechanism that supplies pressure for liquid transfer to the supply tank 11 and the degassing tank 13. As shown in FIG. 1, the pressurizing mechanism 15 has a high-pressure gas supply source 151, a pressurizing pipe 152, a regulator 153, a first pressurizing valve V21, and a second pressurizing valve V22. The high-pressure gas supply source 151 is filled with high-pressure gas (e.g., nitrogen). The upstream end of the pressurizing pipe 152 is connected to the high-pressure gas supply source 151. The regulator 153 is provided on the path of the pressurizing pipe 152. The downstream end of the pressurizing pipe 152 branches into two pipes that are connected to the supply tank 11 and the degassing tank 13, respectively. The first pressurizing valve V21 and the second pressurizing valve V22 are provided on each of the two branched pressurizing pipes 152.

[0036] The gas supplied from the high-pressure gas supply source 151 is adjusted by the regulator 153 to a predetermined pressure higher than atmospheric pressure. When the second pressurizing valve V22 is closed and the first pressurizing valve V21 is opened, gas at the predetermined pressure is supplied from the pressurizing pipe 152 to the supply tank 11. As a result, varnish is pushed out from the supply tank 11 to the first liquid supply pipe 12. Furthermore, when the first pressurizing valve V21 is closed and the second pressurizing valve V22 is opened, gas at the predetermined pressure is supplied from the pressurizing pipe 152 to the degassing tank 13. As a result, varnish is pushed out from the degassing tank 13 to the second liquid supply pipe 14.

[0037] As shown in Fig. 1, a first flow rate sensor 41 is attached to the first liquid supply pipe 12. The first flow rate sensor 41 is disposed between the first liquid supply valve V11 and the degassing tank 13, and between the first filter F1 and the degassing tank 13. The first flow rate sensor 41 measures the flow rate of the varnish passing through the first liquid supply pipe 12. The first flow rate sensor 41 is disposed outside the first liquid supply pipe 12. The first flow rate sensor 41 is a non-contact flow rate sensor that measures the flow rate of the varnish in a non-contact manner without coming into contact with the varnish in the first liquid supply pipe 12.

[0038] As shown in FIG. 1 , the second liquid supply pipe 14 is provided with a second flow rate sensor 42. The second flow rate sensor 42 is disposed between the second liquid supply valve V12 and the degassing tank 13. The second flow rate sensor 42 measures the flow rate of the varnish flowing through the second liquid supply pipe 14. Like the first flow rate sensor 41, the second flow rate sensor 42 is a non-contact flow rate sensor. That is, the second flow rate sensor 42 is disposed outside the second liquid supply pipe 14. The second flow rate sensor 42 measures the flow rate of the varnish in a non-contact manner, without coming into contact with the varnish in the second liquid supply pipe 14.

[0039] Non-contact flow rate sensors may be, for example, ultrasonic or laser sensors. These types of sensors output ultrasonic or laser light radiation waves from an output unit toward the pipe, and detect the frequency change (Doppler effect) of the reflected waves when the radiation waves hit particles in the pipe. The flow rate of the liquid passing through the pipe is then measured based on the detected frequency change.

[0040] The pressure reducing mechanism 16 is a mechanism for reducing the pressure inside the degassing tank 13. As shown in FIG. 1, the pressure reducing mechanism 16 has a pressure reducing pipe 161, a pressure reducing pump 162, and a pressure reducing valve V23. One end of the pressure reducing pipe 161 is connected to the degassing tank 13. The other end of the pressure reducing pipe 161 is connected to an exhaust line inside the factory. The pressure reducing valve V23 and the pressure reducing pump 162 are provided on the path of the pressure reducing pipe 161. When the pressure reducing valve V23 is opened and the pressure reducing pump 162 is operated, the gas inside the degassing tank 13 is sucked into the exhaust line through the pressure reducing pipe 161. This reduces the air pressure inside the degassing tank 13.

[0041] As shown in FIG. 1, a third flow rate sensor 43 is provided in the pressure reduction pipe 161. The third flow rate sensor 43 is disposed between the pressure reduction valve V23 and the degassing tank 13. The third flow rate sensor 43 measures the flow rate of the gas passing through the pressure reduction mechanism 16. The third flow rate sensor 43 may be a contact sensor that comes into contact with the gas in the pipe, or a non-contact sensor that does not come into contact with the gas. By measuring the gas flow rate with the third flow rate sensor 43, the amount of gas released from the liquid varnish in the degassing tank 13 can be measured.

[0042] A switching valve 18 is provided in the second liquid supply pipe 14 downstream of the assist pump P1. The switching valve 18 turns on and off the supply of liquid toward the liquid supply port 19. The switching valve 18 is switched between an open state and a closed state based on a control signal from the control unit 30. A drainage pipe 171 is connected to the second liquid supply pipe 14 between the assist pump P1 and the switching valve 18. As shown in FIG. 1 , the drainage pipe 171 is connected to a drainage line. The varnish that passes through the drainage pipe 171 is sent to the drainage line and discharged. A return pipe may be provided to return the varnish that passes through the drainage pipe 171 to the second liquid supply pipe 14, etc. The drainage pipe 171 is provided with an on-off valve 172. The on-off valve 172 is switched between an open state and a closed state based on a control signal from the control unit 30. The on-off valve 172 opens and closes the drainage pipe 171 to turn on and off the supply of varnish from the second liquid supply pipe 14 to the drainage line.

[0043] A liquid supply port 19 provided at the downstream end of the second liquid supply pipe 14 is connected to a third liquid supply pipe 23 of the coating unit 20. The liquid supply port 19 supplies varnish to the coating unit 20, which is the supply destination.

[0044] Fig. 2 is a perspective view of the coating unit 20 shown in Fig. 1. As shown in Figs. 1 and 2, the coating unit 20 has a stage 21, a slit nozzle 22, a third liquid supply pipe 23, a nozzle holder 24, and a traveling mechanism 25. In the following description, the movement direction of the slit nozzle 22 in the coating unit 20 will be referred to as the "front-rear direction." Additionally, the horizontal direction that is perpendicular to the front-rear direction and parallel to a horizontal plane will be referred to as the "left-right direction."

[0045] The stage 21 is a roughly rectangular parallelepiped holding platform on which the carrier substrate 9 is placed and held. The stage 21 is formed, for example, from a single piece of stone material. The upper surface of the stage 21 is a flat substrate holding surface 211. A large number of vacuum suction holes (not shown) are provided on the substrate holding surface 211. When the carrier substrate 9 is placed on the substrate holding surface 211, the suction force of the vacuum suction holes causes the lower surface of the carrier substrate 9 to be adsorbed to the substrate holding surface 211. This fixes the carrier substrate 9 in a horizontal position on the stage 21. In addition, a plurality of lift pins (not shown) are provided inside the stage 21. When the carrier substrate 9 is removed from the stage 21, the plurality of lift pins protrude above the substrate holding surface 211. This separates the carrier substrate 9 from the substrate holding surface 211.

[0046] The slit nozzle 22 is a nozzle that discharges varnish. The slit nozzle 22 has a nozzle body 221 that extends in the left-right direction. A slit-shaped discharge port 223 that extends in the left-right direction is provided at the lower end of the nozzle body 221. The discharge port 223 faces the upper surface of the carrier substrate 9 placed on the stage 21.

[0047] The third liquid supply pipe 23 is a pipe for supplying varnish to the slit nozzle 22. The upstream end of the third liquid supply pipe 23 is connected to the liquid supply port 19 described above. The downstream end of the third liquid supply pipe 23 is connected to the slit nozzle 22. A main pump P2 is provided on the path of the third liquid supply pipe 23. When the main pump P2 is operated, the varnish supplied from the second liquid supply pipe 14 is introduced into the slit nozzle 22. Then, the varnish is discharged from the discharge port 223 of the slit nozzle 22 toward the upper surface of the carrier substrate 9.

[0048] The nozzle holding part 24 is a mechanism for holding the slit nozzle 22 above the substrate holding surface 211. The nozzle holding part 24 has a bridge part 241 extending in the left-right direction above the stage 21, a pair of support parts 242 supporting both ends of the bridge part 241, and an elevation mechanism 243. When the elevation mechanism 243 is operated, the height of the bridge part 241 changes. This adjusts the height of the slit nozzle 22.

[0049] The traveling mechanism 25 is a mechanism for moving the slit nozzle 22 in the front-rear direction. The traveling mechanism 25 has a pair of rails 251 and a pair of linear motors 252. The pair of rails 251 extend in the front-rear direction near the left and right sides of the stage 21. The pair of rails 251 function as linear guides that regulate the movement direction of the pair of support parts 242 in the front-rear direction. The pair of linear motors 252 move the pair of support parts 242 in the front-rear direction along the rails 251 by magnetic power. As a result, the slit nozzle 22 moves in the front-rear direction together with the nozzle holding part 24.

[0050] When performing the coating process, the coating unit 20 discharges the varnish from the discharge port 223 while moving the slit nozzle 22 back and forth above the carrier substrate 9. In this way, the varnish is applied to the upper surface of the carrier substrate 9.

[0051] 3 is a block diagram showing the connection between the control unit 30 and each unit in the coating apparatus 1. The control unit 30 has a processor 31 such as a CPU, a memory 32 such as a RAM, and a storage unit 33 such as a hard disk drive. The control unit 30 temporarily reads out computer programs and data stored in the storage unit 33 into the memory 32, and the processor 31 performs arithmetic processing based on the computer programs and data, thereby controlling the operation of each unit in the coating apparatus 1. In this way, the coating process on the carrier substrate 9 progresses.

[0052] 3, the control unit 30 is electrically connected to each part in the liquid supply unit 10, such as the above-mentioned stirring mechanism 131, regulator 153, decompression pump 162, first liquid supply valve V11, second liquid supply valve V12, first pressurizing valve V21, second pressurizing valve V22, assist pump P1, first flow rate sensor 41, second flow rate sensor 42, and third flow rate sensor 43. The control unit 30 is also electrically connected to each part in the coating unit 20, such as the above-mentioned lift pins, main pump P2, lifting mechanism 243, and linear motor 252.

[0053] 3, the control unit 30 is electrically connected to a display 311 that displays images, and an input device 312. The input device 312 is a mouse, a keyboard, or a touch panel.

[0054] The control unit 30 functions as a calculation unit that calculates the remaining amount of varnish in the degassing tank 13 based on the output of the first flow rate sensor 41 and the output of the second flow rate sensor 42. Specifically, the processor 31 calculates an integrated flow rate A, which is the total amount of varnish that has passed through the first liquid supply pipe 12 (supply pipe) from a reference time (e.g., the time when the degassing tank 13 is empty) to the present time, based on the output of the first flow rate sensor 41. The integrated flow rate A is the total amount of varnish supplied to the degassing tank 13 from the reference time to the present time. Furthermore, the processor 31 calculates an integrated flow rate B, which is the total amount of treatment liquid that has passed through the second liquid supply pipe 14 (discharge pipe) from the reference time to the present time, based on the output of the second flow rate sensor 42. The integrated flow rate B is the total amount of treatment liquid discharged from the degassing tank 13. The processor 31 then calculates the remaining amount of treatment liquid in the degassing tank 13 by subtracting the integrated flow rate B (total discharge amount) from the integrated flow rate A (total supply amount).

[0055] When the pressure in the degassing tank 13 is reduced by the pressure reducing mechanism 16, the solvent (organic solvent) in the varnish evaporates along with the dissolved gas. When the solvent evaporates in this manner, the amount of varnish remaining in the degassing tank 13 decreases in accordance with the amount of evaporation. Therefore, the processor 31 may calculate the amount of varnish remaining in the degassing tank 13 based on the flow rate of the gas detected by the third flow sensor 43.

[0056] Specifically, the processor 31 calculates an integrated flow rate C, which is the total amount of gas that has passed through the decompression pipe 161 (exhaust pipe) from a reference time to the present time. This integrated flow rate C corresponds to the total amount of gas released from the liquid varnish in the degassing tank 13. The processor 31 then calculates a total evaporation amount C1 of the solvent from the integrated flow rate C. The calculation of the total evaporation amount C1 of the solvent may be performed using a conversion formula or a look-up table prepared in advance. Alternatively, a concentration sensor that detects the concentration of the solvent in the gas may be attached to the decompression pipe 161. The processor 31 may then calculate the total evaporation amount C1 of the solvent based on the integrated flow rate C and the output of the concentration sensor. The processor 31 then calculates the remaining amount of varnish in the degassing tank 13 by subtracting the integrated flow rate B and the total evaporation amount C1 from the integrated flow rate A.

[0057] <Effects> According to the liquid supply unit 10 of the coating apparatus 1, the first flow rate sensor 41 and the second flow rate sensor 42 measure, in a non-contact manner, the flow rates of the highly viscous varnish passing through the first liquid supply pipe 12 and the second liquid supply pipe 14, respectively. Therefore, based on the outputs of the first flow rate sensor 41 and the second flow rate sensor 42, it is possible to accurately measure the integrated flow rate A of the varnish supplied to the degassing tank 13 and the integrated flow rate B of the varnish discharged from the degassing tank 13. Therefore, based on the difference between the integrated flow rates A and B, it is possible to accurately calculate the remaining amount of varnish in the degassing tank 13.

[0058] FIG. 4 is a schematic diagram of the degassing tank 13 while the varnish is being discharged. In the example shown in FIG. 4, an outlet 133 connected to the second liquid supply pipe 14 is provided in the center of the bottom surface of the degassing tank 13. When the varnish is being discharged from the degassing tank 13, the varnish flows into the outlet 133 while adhering to the wall surfaces of the degassing tank 13. As a result, as shown in FIG. 4, the varnish liquid surface 91 may be inclined obliquely relative to the horizontal. For this reason, even if an attempt is made to measure the height of the varnish liquid surface 91 in the degassing tank 13 with a level sensor, it is difficult to accurately measure the remaining amount of varnish in the degassing tank 13. Furthermore, as the varnish is degassed, many air bubbles are generated at the varnish liquid surface 91. For this reason, it is difficult to accurately measure the height of the liquid surface 91 with a level sensor. In contrast, the liquid supply unit 10 calculates the remaining amount of varnish based on the flow rate of varnish flowing into the degassing tank 13 and the flow rate of varnish flowing out of the degassing tank 13. Therefore, the remaining amount of varnish in the degassing tank 13 can be measured with high accuracy, regardless of the shape of the liquid surface 91.

[0059] Furthermore, the first flow rate sensor 41 and the second flow rate sensor 42 are available at a lower price than a weighing scale that can measure the weight of the degassing tank 13 with high accuracy. Therefore, the equipment cost of the liquid supply unit 10 can be reduced compared to when the remaining amount is measured with a weighing scale.

[0060] Furthermore, the total evaporation amount C1 of the solvent in the varnish can be calculated based on the output of the third flow sensor 43 and the cumulative flow rate C of the gas released from the liquid varnish in the degassing tank 13. Therefore, by subtracting the total evaporation amount C1 of the solvent from the cumulative flow rate A, the remaining amount of varnish in the degassing tank 13 can be calculated with even greater accuracy.

[0061] <2. Modifications> Although the embodiments have been described above, the present invention is not limited to the above and various modifications are possible.

[0062] Fig. 5 is a diagram showing a degassing tank 13 according to a modified example. As shown in Fig. 5, a plurality of first liquid supply pipes 12 may be connected to the degassing tank 13 as supply pipes. In this case, a first flow rate sensor 41 may be attached to each of the plurality of first liquid supply pipes 12, thereby enabling the total amount of varnish supplied to the degassing tank 13 to be properly measured. Also, as shown in Fig. 5, a plurality of second liquid supply pipes 14 may be connected to the degassing tank 13 as discharge pipes. In this case, a second flow rate sensor 42 may be attached to each of the plurality of second liquid supply pipes 14, thereby enabling the total amount of varnish discharged from the degassing tank 13 to be properly measured.

[0063] Tanks other than the degassing tank 13 (for example, the supply tank 11) may also be provided with a first flow rate sensor and a second flow rate sensor for calculating the remaining amount of varnish in the tank.

[0064] Although the present invention has been described in detail, the above description is merely illustrative in all respects and does not limit the present invention. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present invention. The configurations described in the above embodiments and variations can be combined or omitted as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0065] 1 Coating device 10. Liquid supply unit (liquid supply device) 12 First liquid supply pipe (supply pipe) 13 Degassing tank 14 Second liquid supply pipe (discharge pipe) 15 Pressure mechanism 20 Coating unit 22 Slit nozzle 30 Control unit (calculation unit) 41 First flow sensor 42 Second flow sensor 43 Third flow sensor 161 Pressure reducing piping (exhaust piping) 162 Pressure reducing pump

Claims

1. A liquid supply device for supplying a processing liquid, a tank capable of storing a high-viscosity processing liquid; a supply pipe for supplying the processing liquid into the tank; a discharge pipe for discharging the treatment liquid to the outside of the tank; a first flow rate sensor configured to detect a flow rate of the processing liquid passing through the supply pipe outside the supply pipe; a second flow rate sensor configured to detect the flow rate of the treatment liquid passing through the discharge pipe outside the discharge pipe; a calculation unit that calculates the remaining amount of the processing liquid in the tank based on an output of the first flow rate sensor and an output of the second flow rate sensor; Equipped with The liquid supply device, wherein the first flow rate sensor or the second flow rate sensor is a non-contact type flow rate sensor that does not come into contact with the processing liquid in the supply pipe.

2. The liquid supply device according to claim 1, a pressure reducing unit that reduces the pressure inside the tank; an exhaust pipe for discharging gas to the outside of the tank; a third flow rate sensor for detecting the flow rate of the gas passing through the exhaust pipe; Furthermore, The calculation unit calculates the remaining amount of the processing liquid in the tank based on the output of the third flow rate sensor.

3. The liquid supply device according to claim 1 or 2, a pressurizing unit that pressurizes the inside of the tank; The liquid supply device further comprises:

4. The liquid supply device according to claim 1 or 3, The viscosity of the treatment liquid is 1,000 cP or more and 10,000 cP or less.

5. A liquid supply device according to any one of claims 1 to 4, The non-contact flow sensor is a liquid supply device that is an ultrasonic or laser sensor that outputs ultrasonic or laser light irradiation waves from an output unit toward a pipe and detects the frequency change of the reflected waves that are reflected when the irradiation waves hit particles in the pipe using a detection unit.

6. A coating device comprising: The liquid supply device according to any one of claims 1 to 5; a nozzle that discharges the processing liquid supplied from the liquid supply device; An application device comprising:

Images