JP5757777B2 - Substrate coating method, substrate coating apparatus, and organic electroluminescent device manufacturing method using the same - Google Patents

Description

  The present invention relates to a substrate coating method and a substrate coating apparatus for coating a coating solution on a substrate, and a method for manufacturing an organic electroluminescent element using the method.

  In an electroluminescence (EL) element, a light emitting layer sandwiched between an anode and a cathode is formed on a transparent substrate, and when a voltage is applied between the electrodes, electrons and holes injected into the light emitting layer as carriers. It emits light by excitons generated by recombination of. EL elements are roughly classified into an organic EL element using an organic substance as a fluorescent material of a light emitting layer and an inorganic EL element using an inorganic substance. In particular, the organic EL element can emit light with high luminance at a low voltage, and various emission colors can be obtained depending on the type of fluorescent material. In addition, various types of organic EL elements can be easily manufactured as a flat light-emitting panel. Used as a display device or a backlight. Furthermore, in recent years, a device corresponding to high luminance has been realized and attention has been paid to using it for a lighting fixture.

  FIG. 12 shows a cross-sectional configuration of a general organic EL element. In the organic EL element 101, a light-transmitting anode layer 111 is provided on a light-transmitting substrate 70, and a hole injection layer 121, a hole transport layer 122, and a light emitting layer are formed on the anode layer 111. An organic layer 120 consisting of 123 is provided. A cathode layer 112 having light reflectivity is provided on the organic layer 120. Then, when a voltage is applied between the anode layer 111 and the cathode layer 112, light emitted from the light emitting layer 123 of the organic layer 120 passes through the anode layer 111 and the substrate 70 and is extracted. In addition, a layer (not shown) containing light diffusing fine particles for improving light extraction efficiency may be formed between the anode layer 111 and the organic layer 120.

  In such an organic EL element 101, if the organic layer 120 is not formed on the anode layer 111 so as to cover the fine particles, the anode layer 111 and the cathode layer 112 are close to each other and a short circuit occurs between the electrodes. The reliability of the device may be reduced. Therefore, a method for forming the organic layer 120 on the anode layer 111 by coating is known. According to the application, in the step of applying and drying the organic material constituting the organic layer 120, the fine particles are covered with the organic material, or solidified with the organic material entering the gap between the fine particles and the substrate 70 for insulation. Since it works as a layer, the occurrence of a short circuit can be suppressed.

  As a method for forming such an organic solvent by coating, a method for manufacturing an organic EL element in which an organic layer is formed by a slit coating method, a spin coating method, an ink jet method, a screen printing method, or the like is known (for example, patents). Reference 1). In the slit coating method, first, a substrate is placed on the opposite side of the nozzle discharge port in which a slit-like opening having a parallel surface with a gap of several tens of microns is formed, and the nozzle and the substrate are brought close to each other. And it is the method of apply | coating a coating liquid on a board | substrate by horizontally moving a board | substrate, with the coating liquid discharged from a nozzle being in the state which contacted the board | substrate. This slit coating method can form an organic layer with high material use efficiency in a short time as compared with other methods for forming an organic layer such as vapor deposition.

  By the way, in the application by the slit coat method, if the application is continuously performed without taking time, the application liquid in the nozzle is sequentially replaced with a new application liquid, and the discharge amount from the nozzle is kept constant, An organic layer having a uniform film thickness can be formed. However, in the actual production of organic EL elements, in addition to the coating by the slit coating method, for example, a step of forming other layers by vapor deposition is included, and the processing time of these other steps is usually the slit coating method. It becomes longer than the coating process using. Therefore, in the coating process by the slit coating method, it is necessary to provide a waiting time appropriately every time a predetermined number of organic layers are formed.

  However, during this waiting time, the coating solution may dry and change its viscosity, or the coating solution may come into contact with the outside air at the nozzle opening and oxidize, changing its viscosity, concentration, and components, resulting in liquid deterioration. If it does so, when waiting time passes and application | coating is restarted, there exists a possibility that the discharge amount may become unstable easily and the film thickness of the organic layer formed may become non-uniform | heterogenous. In addition, the coating liquid is oxidized during the standby time, the components are denatured, and electric characteristics such as charge mobility are changed, which may cause variation in the light emission characteristics of the organic EL element. Therefore, in the manufacturing method described in Patent Document 1, in this waiting time, the nozzle and the substrate are joined at the liquid surface of the coating liquid to prevent the coating liquid from being dried in the nozzle. Yes.

International Publication WO10 / 146998 Pamphlet

  However, when waiting for a long time in a state where the liquid level is bonded in this way, the liquid level itself is contaminated with the atmosphere, and as a result, the coating liquid inside the nozzle may be contaminated. In addition, if the organic material in the coating liquid is left in a stationary state, the coating liquid in contact with the inner wall of the nozzle is deposited on the periphery of the nozzle, and as a result, the discharge amount may vary and the film thickness may not be uniform. is there. However, when the nozzle and the substrate are not joined at the liquid level of the coating liquid, the coating liquid in the nozzle dries, the nozzle outlet is clogged, and stable coating cannot be performed.

  The present invention solves the above-described problems, and provides a substrate coating method, a substrate coating apparatus, and an organic electroluminescence device using the same that can suppress liquid deterioration due to drying and oxidation of the coating liquid in the slit nozzle. An object of the present invention is to provide a manufacturing method of a cent element.

In order to solve the above problems, a substrate coating method according to the present invention is a substrate coating method in which a coating solution is applied onto a substrate using a slit nozzle, and the substrate is intermittently transported from the slit nozzle. A first step of applying a coating solution to form a coating film; a second step of waiting after applying the coating solution on the next substrate after the first step; and the first step Before the step, a third step of discharging the coating liquid to a roller portion disposed at a position below the slit nozzle from the discharge port of the slit nozzle with a gap, and in the second step, The amount of the coating liquid ejected from the slit nozzle in the third step is larger than the amount of the coating liquid ejected from the slit nozzle in the third step. it is also less And butterflies.

  In the substrate coating method, the coating solution is stored in an inner housing portion of a double-structured coating solution storage portion having an inner housing portion and an outer housing portion, and the outer housing portion and the inner housing portion. By injecting fluid between them and pressurizing the inner housing part, the liquid is sent to the outside of the coating liquid storage part, and does not come into contact with the outside air in the process of liquid feeding until it is discharged from the slit nozzle. It is preferable.

  The substrate coating method preferably includes a fourth step of wiping off the coating liquid adhering to the outer surface of the slit nozzle between the second step and the third step.

  Moreover, the manufacturing method of the organic electroluminescent element which concerns on this invention forms the film | membrane which comprises an organic electroluminescent element by the said board | substrate coating method.

  Moreover, the manufacturing method of the organic electroluminescent element which concerns on this invention further forms the film | membrane which comprises an organic electroluminescent element on the coating film formed by the said board | substrate coating method.

Further, the substrate coating apparatus according to the present invention includes a coating solution storage unit that stores a coating solution, a coating unit that coats the coating solution using a slit nozzle, and the coating solution from the coating solution storage unit to the slit nozzle. A coating liquid feeding part that feeds liquid without touching the outside air, a roller liquid receiving part that slidably arranges a roller part below the slit nozzle, and a substrate intermittently conveyed below the slit nozzle and a substrate transfer unit for the application part, prior to applying the coating solution to the waiting time and the substrate not coated with the coating solution to the substrate, and discharging the coating liquid to the roller unit, the The amount of the coating liquid discharged during the standby time is smaller than the amount of the coating liquid discharged from the slit nozzle before applying the coating liquid to the substrate .

  In the substrate coating apparatus, the coating solution storage unit has a double structure including an inner storage unit and an outer storage unit, and the coating solution is stored in the inner storage unit, and the outer storage unit and the inner storage unit It is preferable that the fluid is injected between the container and the inner container is pressurized, so that the liquid is fed to the outside of the coating liquid storage unit.

  The said board | substrate coating device WHEREIN: It is preferable to provide the wiping part which wipes off the coating liquid adhering to the outer surface of the said slit nozzle.

  According to the present invention, since the coating liquid in the slit nozzle is appropriately circulated during the standby time, liquid deterioration such as drying and oxidation of the coating liquid in the slit nozzle can be suppressed.

(A) is a perspective view of the board | substrate coating apparatus which enforces the board | substrate coating method which concerns on the 1st Embodiment of this invention, (b) is a fragmentary sectional view of the slit nozzle and roller part of the apparatus. The side view which shows the structure of the coating liquid storage part and slit nozzle in the apparatus. The figure which shows the liquid feeding path | route of the coating liquid in the apparatus. (A) is a perspective view for demonstrating the 1st process in the substrate coating apparatus using the substrate coating method, (b) is a partial cross section figure of the slit nozzle and roller part of the apparatus. The figure which shows each process of the board | substrate coating method in 1st Embodiment. (A) is a perspective view for demonstrating the 1st process in the substrate coating apparatus using the substrate coating method, (b) (c) is a partial cross section figure of the slit nozzle and roller part of the apparatus. (A) is a perspective view for demonstrating the 2nd process in the substrate coating apparatus which enforces the substrate coating method, (b) is a partial cross section figure of the slit nozzle and roller part of the apparatus. (A) is a perspective view for demonstrating the 2nd and 3rd process in the board | substrate coating device using the board | substrate coating method, (b) (c) is a fragmentary sectional view of the slit nozzle and roller part of the apparatus. . The figure which shows each process of the board | substrate coating method in 2nd Embodiment. (A) thru | or (c) is a perspective view for demonstrating the 4th process in the substrate coating apparatus using the substrate coating method. The partial cross section figure which shows the structure of the wiping off part in a board | substrate coating device. The side sectional view showing the composition of a general organic electroluminescence element.

  A substrate coating method according to a first embodiment of the present invention and a substrate coating apparatus for performing the coating method will be described with reference to FIGS. The substrate coating apparatus 1 of this embodiment forms a film constituting an organic electroluminescence element (hereinafter referred to as an organic EL element) by coating. As shown in FIGS. 1A and 1B, the substrate coating apparatus 1 touches the coating liquid 20 with the coating liquid storage section 2 for storing the coating liquid 20, the coating section 3 for coating the coating liquid 20, and the coating liquid 20. The coating liquid feeding section 4 that feeds the liquid without any problem, and the roller liquid receiving section 5 in which the roller section 50 is slidably disposed. Further, the substrate coating apparatus 1 intermittently disposes the waste liquid tank 6 (see FIG. 3 described later) from which the coating liquid 20 that has not been used for coating is discharged and the substrate 70 (see FIG. 4 described later) below the coating unit 3. And a substrate transfer unit 7 for transferring the substrate. Further, the substrate coating apparatus 1 includes a control unit (not shown) that drives and controls the coating unit 3, the coating liquid feeding unit 4, the roller liquid receiving unit 5, and the substrate transport unit 7. As this control unit, individual units may be used for each of the coating unit 3, the coating liquid feeding unit 4, the roller liquid receiving unit 5, and the substrate transporting unit 7, or those that collectively drive and control them. May be used.

  The application unit 3 is provided with a slit nozzle 31 in which a slit-like discharge port 30 is formed in a hanging direction, a lifting member 33 for moving the slit nozzle 31 up and down, and both ends of the slit nozzle 31, and the slit nozzle 31 and the lifting member 33. And a connecting portion 34 for connecting the two. The connecting portion 34 detachably holds the slit nozzle 31 with respect to the elevating member 33 so that the longitudinal direction thereof is horizontal.

  The slit nozzle 31 includes a box-shaped nozzle storage unit 35 that stores a predetermined amount of the coating liquid 20 above the discharge port 30. An inlet 36 for the coating liquid 20 is provided on the side of the nozzle storage unit 35. On the bottom surface of the nozzle storage unit 35, an outflow groove (not shown) through which the coating liquid 20 flows out to the discharge port 30 is formed in a slit shape having substantially the same shape as the discharge port 30. That is, when the coating liquid 20 is supplied from the injection port 36, the coating liquid 20 is filled into the nozzle storage unit 35, and when the coating liquid 20 is continuously supplied at a constant pressure, the coating liquid 20 is discharged from the outflow groove. From the discharge port 30. The outer shape from the nozzle reservoir 35 to the discharge port 30 is configured as an inclined surface 32 that tapers toward the discharge port 30.

  The elevating member 33 is provided on a pair of columnar members 37, opposing surfaces of the columnar member 37, a vertical rail member 38 to which the coupling portions 34 at both ends of the slit nozzle 31 are coupled, and the slit nozzle 31 to the vertical rail member 38. And a drive unit (not shown) that moves up and down along the line. The columnar member 37 is fixed to a pedestal (not shown) of the substrate coating apparatus 1. The drive unit operates according to a drive control signal from the control unit, and moves the slit nozzle 31 up and down to an arbitrary height.

  The coating solution feeding unit 4 includes a coating solution piping 40 that serves as a feeding channel for the coating solution 20, a pump 41 that sucks the coating solution 20 from the coating solution storage unit 2 and feeds it to the coating unit 3, and a coating solution piping. And a plurality of air operated valves (AOV) 42 for controlling the flow rate of the coating liquid 20 flowing through 40. The coating liquid pipe 40, the pump 41, and the AOV 42 each have a sealed structure so that the coating liquid 20 can be fed from the coating liquid storage unit 2 to the coating unit 3 (slit nozzle 31) without touching the outside air. .

  The roller liquid receiving part 5 includes a roller part 50 that receives the coating liquid 20 discharged from the slit nozzle 31, a roller support part 51 that houses the roller part 50, and a sliding support that slides the roller support part 51 in the horizontal direction. Unit 52.

  The roller portion 50 is held at a position higher than the bottom surface of the roller support portion 51 so as to have a rotation axis along the longitudinal direction of the slit nozzle 31. The surface of the roller unit 50 is preferably formed from a material having a small contact angle with the coating liquid 20.

  The roller support portion 51 has an opening 53 above the roller portion 50, and the coating liquid 20 discharged from the slit nozzle 31 is applied to the roller portion 50 through the opening 53. Further, the inside of the roller support portion 51 is formed as a container portion 54 that can be filled with a predetermined amount of solvent, and in this container portion 54, a solvent 55 having an affinity for the coating solution 20 has an upper surface position. The roller portion 50 is filled up to a position in contact with the lower surface. Furthermore, a squeegee 56 for removing the coating liquid 20 adhering to the roller unit 50 is provided inside the roller support unit 51.

  The sliding support portion 52 is provided on the upper surface of the pair of support members 57, the horizontal rail member 58 to which the roller support portion 51 is connected, and the slit nozzle 31 is moved up and down along the vertical rail member 38. A drive unit (not shown). The support members 57 are arranged at intervals slightly wider than the width of the slit nozzle 31 and slidably support the roller support portion 51 at a position higher than the height of the substrate transport portion 7 that transports the substrate 70. The support member 57 is fixed to a base (not shown) of the substrate coating apparatus 1. The drive unit operates according to a drive control signal from the control unit, and the roller support unit 51 is positioned at a position where the opening 53 (roller unit 50) is directly below the slit nozzle 31 or the roller support unit 51 is connected to the slit nozzle 31. Slide it to a position that does not interfere with the up and down movement.

  As shown in FIG. 2, the coating solution storage unit 2 has a double structure including an inner storage unit 21 and an outer storage unit 22, and the coating solution 20 is stored in the inner storage unit 21. The inside of the inner housing part 21 and the outer housing part 22 is individually sealed by the connection valve 23. For example, a bag-like container that is easily deformed by the external pressure of a plastic container is used for the inner housing portion 21. The inner container 21 is sealed with, for example, an amount of the coating liquid 20 that is used for manufacturing a coating film for one month. A cylindrical or box-shaped container having a predetermined strength is used for the outer housing portion 22. The connection valve 23 connects the coating liquid piping 40 into the inner housing portion 21 so as not to impair the sealing performance in the inner housing portion 21. An air pipe 24 is connected to the inside of the outer housing portion 22 through the connection valve 23. Then, fluid (air) is injected between the inside of the outer housing portion 22 and the outside of the inner housing portion 21, and the inner housing portion 21 is pressurized, whereby the coating liquid 20 in the inner housing portion 21 is The liquid is fed to the outside of the coating liquid storage unit 2. The inner storage portion 21, the outer storage portion 22, and the connection valve 23 are preferably configured as a cartridge. When the coating solution 20 is used up, the cartridge is replaced so that a new coating solution 20 is always easily supplied to the slit nozzle 31. Can be supplied.

  The coating liquid 20 is produced by mixing a functional material for realizing the function of the coating layer to be formed and a solvent for dispersing the functional material. The coating can be used regardless of the molecular weight of the material as compared with vapor deposition and the like, and the functional material used in the coating liquid 20 of the present embodiment includes various materials from low molecular materials to high molecular materials. Can be used. Here, the polymer refers to a molecule having two or more repeating units, and includes oligomers and the like.

  Here, the material used for the coating liquid 20 in the case where the coating layer to be produced is a hole injection / transport layer known as one of the films constituting the organic EL element is shown below. Examples of the low molecular weight material include α-NPD (4,4-bis [N- (2-naphthyl) -N-phenyl-amino] biphenyl, spiro-NPB (N, N′-bis [naphthalen-1-yl). ] -N, N'-bis [phenyl] -9,9-spirobifluorene), spiro-TAD (2,2 ', 7,7'-tetrakis [N, N-diphenylamino] -9,9'- Spirobifluorene), 2-TNATA (4,4 ′, 4 ″ -tris [2-naphthylphenylamino] triphenylamine, etc. can be used. Also, International Publication WO2001 / 49806 or JP2006-173550A. Inducts having an azatriphenylene skeleton represented by HAT-CN6 (1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile) described in the publication In addition, as a polymer material, P3HT (poly-3-hexylthiophene), PEDOT / PSS (poly3,4-ethylenedioxythiophene / polystyrene sulfonic acid), MEH-PPV ( Poly- [2methoxy-5- (2-ethyl-hexyloxy) -1,4-phenylene-vinylene)], polyaniline, polypyrrole, PVK (polyvinylcarbazole), etc. can be used, and the conductivity of these can be improved. In order to achieve this, an electron-accepting compound may be doped.There is no particular limitation on the electron-accepting compound, but ferric chloride, ferric bromide, which are described in JP-A-2003-272860, Ferric iodide, aluminum chloride, aluminum bromide, aluminum iodide, gallium chloride, gallium bromide, gallium iodide Indium chloride, indium bromide, indium bromide, indium iodide, antimony chloride, arsenic pentafluoride, boron trifluoride and other inorganic compounds such as DDQ (dicyano-dichloroquinone), TNF (trinitrofluorenone), TCNQ (tetracyano) Quinodimethane), organic compounds such as F4-TCNQ (tetrafluoro-tetracyanoquinodimethane), etc. Further, examples of the solvent include water, IPA (isopropyl alcohol), butyl acetate, cyclohexanol, ethylene glycol, propylene. Glycol, chloroform, chlorobenzene, dichloroethane, DMF (N-N dimethylformamide), DMSO (dimethyl sulfoxide), etc. can be used, and a mixed solvent in which the viscosity and surface energy are changed by appropriately mixing them can be used. Mode That.

  Next, the liquid supply path of the coating liquid 20 will be described with reference to FIG. The coating liquid 20 stored in the inner storage section 21 of the coating liquid storage section 2 is taken into the pump 41, pressure is applied by the pump 41, and the liquid is sent to the slit nozzle 31 through the coating liquid piping 40. . At this time, the flow pressure of the coating liquid 20 is controlled by the AOV 42. A part of the coating liquid 20 staying in the pump 41 or the slit nozzle 31 is drained into the waste liquid tank 6 via the waste liquid pipe 60. Further, the coating liquid 20 discharged from the slit nozzle 31 to the roller unit 50 and flowing out to the container unit 54 of the roller support unit 51 is also discharged into the waste liquid tank 6 through the waste liquid pipe 60. In the above-described liquid feeding path of the coating liquid 20, at least the liquid feeding of the coating liquid 20 from the coating liquid storage unit 2 to the slit nozzle 31 is performed so that the coating liquid 20 does not come into contact with the outside air in the process.

  By the way, if the coating liquid 20 is stored in a storage tank or the like for a long time in contact with the atmosphere, the functional material is oxidized or the solvent is evaporated to change the material concentration. As a result, the film thickness after coating varies. There is a risk of non-uniformity. Further, in the conventional method in which the coating liquid 20 is added to a storage tank or the like, the concentration of the coating liquid may be uneven in the storage tank, or the old coating liquid 20 may accumulate at the bottom of the storage tank. On the other hand, in the present embodiment, the coating liquid 20 is stored in the exchangeable dedicated coating liquid storage unit 2, and in the liquid feeding path from the coating liquid storage unit 2 to the slit nozzle 31, as described above. It is blocked from the outside air. Therefore, oxidation of the functional material and the like contained in the coating liquid 20 can be prevented. Moreover, since the coating liquid storage part 2 is comprised so that the coating liquid 20 may be sent outside by pressurizing the inner storage part 21, the density | concentration of the coating liquid 20 in the inner storage part 21 is comprised. It is possible to suppress unevenness and accumulation of old coating liquid.

  As shown in FIGS. 4A and 4B, the substrate transfer unit 7 includes a rail (not shown) in which a transfer stand 71 for transferring the substrate 70 is provided on a base (not shown) of the substrate coating apparatus 1. It is slidable along. A pulley 72 is provided on the conveyance table 71, and this pulley 72 is placed on the rail of the base of the substrate coating apparatus 1, and the conveyance table 71 is slidable in parallel with the roller support portion 51. Unlike the roller support 51, the substrate transport unit 7 moves the transport table 71 on which the substrate 70 is placed at a constant speed in one direction by pulling a drive unit (not shown).

  As the substrate 70, for example, a rigid transparent glass plate such as soda glass or non-alkali glass is used, but is not limited thereto. For example, a flexible transparent plastic plate such as polycarbonate or polyethylene terephthalate, a metal film made of Al, copper (Cu), stainless steel, or the like can be used.

  Next, the substrate coating method of this embodiment will be described with reference to FIGS. 5 to 8 in addition to the above-described drawings. In the substrate coating method of this embodiment, a first process, a second process, and a third process described below are sequentially repeated as shown in FIG. The first step, the second step, and the third step are not necessarily performed in this order. The second step is performed after the first step, and the third step is performed by the first step. What is necessary is just to be performed before a process, for example, a process different from these may be performed between a 2nd process and a 3rd process.

  Here, a 1st process is a process of apply | coating the coating liquid 20 from the slit nozzle 31, and forming a coating film on the board | substrate 70 conveyed intermittently. The second step is a step of waiting without applying the coating liquid 20 on the substrate 70. The third step is a step of discharging the coating liquid 20 to the roller portion 50 disposed at a position below the slit nozzle 31 from the discharge port 30 of the slit nozzle 31 with an interval. In the second step, the coating liquid 20 is discharged from the slit nozzle 31 to the roller unit 50. The discharge in the second step is preferably performed intermittently every predetermined period, but may be performed only once depending on the length of the standby time or the property of the coating liquid 20.

  Each of the first step, the second step, and the third step will be described in more detail. Here, a coating method starting from the third step as shown in FIG. 5 will be described.

  In the third step, as shown in FIGS. 1A and 1B, first, the roller portion 50 and the roller support portion 51 that supports the roller portion 50 are disposed immediately below the slit nozzle 31. And the coating liquid 20 is inject | poured into the nozzle storage part 35 from the coating liquid storage part 2 through the coating liquid sending part 4 (pump 41), without touching external air. As shown in the figure, when the injection port 36 is provided in the vicinity of the center in the longitudinal direction of the nozzle storage unit 35, the coating liquid 20 accumulates in the vicinity of the center in the nozzle storage unit 35 in the initial stage of injection. The discharge amount of the coating liquid 20 in the vicinity of the center increases, and the discharge amount on both ends decreases. However, if the nozzle 20 is continuously filled with the coating liquid 20 and the discharge to the roller unit 50 is continued for a predetermined time, the discharge amount of the coating liquid 20 can be made uniform along the longitudinal direction of the discharge port 30. can do. Note that the predetermined time referred to here varies depending on the concentration of the coating liquid 20, the pressure at which the coating liquid 20 is injected, the temperature, and the like. This third step is a process for equalizing the discharge amount from the discharge port 30. This process is called priming, and the roller unit 50 that receives the discharged coating liquid 20 is called a priming roller. Thus, the third step is completed, and thereafter, the first step is promptly performed.

  In the first step, as shown in FIGS. 4 (a) and 4 (b), the substrate 70 is transported by the substrate transport section 7 directly below the slit nozzle 31, and the roller section 50 and the roller support for supporting the roller section 50 are supported. The part 51 is slid to a position that does not hinder the vertical movement of the slit nozzle 31. In addition, the board | substrate 70 may already be conveyed by the 3rd process (not shown in Fig.1 (a)). Next, as shown in FIGS. 6A and 6B, the elevating member 33 lowers the slit nozzle 31 so that the discharge port 30 of the slit nozzle 31 is close to a position slightly spaced. Then, the coating liquid 20 is applied onto the substrate 70 from the slit nozzle 31. At this time, since the coating liquid 20 applied from the discharge port 30 of the slit nozzle 31 is uniformly applied along the longitudinal direction of the discharge port 30 in the third step, the end surface of the coating film 20 ′ on the substrate 70. Can be formed linearly.

  At the same time as the coating liquid 20 is applied onto the substrate 70, the substrate transport unit 7 moves the substrate 70 at a constant speed, as shown in FIG. 6C. At this time, the application liquid 20 is applied from the application unit 3 at a constant application amount. Thereby, the coating film 20 ′ having a uniform thickness is formed on the substrate 70. Thus, the first process is completed.

  If the substrate 70 is moved and applied relative to the slit nozzle 31 with a gap between the slit nozzle 31 and the substrate 70 as in the first step, the slit nozzle 31 is fixed. It is easier to produce a uniform coating film than when the substrate 70 is moved. This is because when the slit nozzle 31 is moved, the ejection amount becomes unstable due to vibration, and a uniform film thickness cannot be obtained. In addition, when the size of the substrate 70 is large, the substrate transport unit 7 for moving the substrate 70 becomes large, so it is preferable to apply the coating by moving the slit nozzle 31 rather.

  When the application of the coating liquid 20 to the substrate 70 is completed a predetermined number of times, the ejection of the coating liquid 20 from the ejection port 30 is stopped. Then, the process proceeds to the second step of waiting without applying the coating liquid 20 on the substrate 70. The process of manufacturing an organic EL element includes a process of forming an organic layer, a process of forming a cathode layer, and the like, and a general organic layer is formed from a plurality of films as shown in FIG. Therefore, a process for forming these plural films is required. The substrate coating method of this embodiment is also used as one (or a plurality of) steps for forming this type of film. However, depending on the type of the organic layer or the like, there are cases where it is not suitable for coating or other film forming methods such as vapor deposition are suitable, and the time required for these other film forming methods is different. For example, when a light-emitting layer is formed by vapor deposition after forming a hole transport layer of an organic EL element by the substrate coating method of the present embodiment, the vapor deposition usually requires more time than coating. It is necessary to wait for a predetermined time for the coating process performed earlier. The second step corresponds to this waiting time.

  In the second step, first, as shown in FIGS. 7A and 7B, the elevating member 33 has the discharge port 30 of the slit nozzle 31 slightly higher than the upper surfaces of the roller unit 50 and the roller support unit 51. The slit nozzle 31 is raised so as to be in the position. Thereafter, as shown in FIGS. 8A and 8B, the roller portion 50 and the roller support portion 51 that supports the roller portion 50 are slid directly below the slit nozzle 31. Then, as shown in FIG. 8C, the coating liquid 20 is discharged from the discharge port 30 of the slit nozzle 31 to the roller unit 50. This discharge is not continuously performed during the second step, but is intermittently performed at predetermined time intervals as shown in FIG.

  In this way, in the second step, which is the waiting time, if the coating liquid 20 is intermittently discharged from the slit nozzle 31 to the roller unit 50, the coating liquid 20 is appropriately circulated. Drying of the coating liquid 20 can be suppressed. Further, it is possible to prevent the functional material in the coating liquid 20 from being deposited around the discharge port 30 of the slit nozzle 31 and being modified.

  The discharge of the coating liquid 20 in the second step is performed at an appropriate frequency according to the length of the standby time, the properties of the coating liquid 20, and the like. If this frequency is too high, the coating liquid 20 is wasted, and if it is too low, drying of the slit nozzle 31 cannot be suppressed. This frequency is set to an optimum number in consideration of the environmental temperature, the viscosity of the coating liquid, and the like. For example, if the temperature is 23 to 27 ° C. and the viscosity is 1 to 10 cP, the frequency is desirably 5 to 10 times / hour. In the example shown in the figure, a case where three discharges are performed in one second step is shown. However, the present invention is not limited to this, and as described above, only one discharge may be performed. Good.

  Moreover, it is preferable that the amount of the coating liquid 20 discharged in the second step is smaller than the amount of the coating liquid 20 discharged from the slit nozzle 31 in the third step. Since the third step serves as a dummy coating performed immediately before coating on the substrate 70, it is necessary to discharge a large amount of coating liquid 20 to some extent. In contrast, the discharge of the coating liquid 20 in the second step only needs to circulate the coating liquid 20 to such an extent that the drying of the slit nozzle 31 can be suppressed. Good. Further, in the second step, the coating liquid 20 is discharged a plurality of times. Therefore, if the amount of the coating liquid 20 per one time is reduced, the discarded coating liquid 20 can be reduced and wasteful. Can be suppressed.

  As described above, according to the substrate coating method of the present embodiment, the drying of the slit nozzle 31 is suppressed and the coating liquid 20 is coated on the substrate 70 even when there is a waiting time in the substrate coating process. At this time, the new coating liquid 20 can always be supplied to the slit nozzle 31. As a result, a desired coating film can be produced without causing liquid deterioration due to oxidation or the like of the coating solution 20. Further, even when a film constituting an organic EL element is formed by using this substrate coating method and a substrate coating apparatus for carrying out the same, a desired coating film can be produced and a highly reliable organic EL element Can be manufactured.

  The substrate coating method of the present embodiment can be particularly suitably used for forming the first organic film on the substrate 70 of the organic EL element. Since a substrate with a transparent electrode (anode layer 111) is generally used as the substrate 70, it is used here for forming the hole injection layer 121 and the hole transport layer 122 as shown in FIG. It is preferable. In this way, as described above, even when fine particles are present on the substrate 70, the fine particles can be covered with the coating film, and a short circuit of the counter electrode can be prevented. Moreover, the unevenness | corrugation of board | substrate itself and the fine unevenness | corrugation of the surface of the anode layer 111 can also be planarized with a coating film.

  Moreover, the film which comprises an organic EL element can further be formed on the coating film formed by the board | substrate coating method of this embodiment. This is because, for example, an organic layer containing a polymer material is formed by the substrate coating method of the present embodiment, and then an organic layer containing a low molecular material is formed by a vapor deposition technique, so that a hybrid type organic EL element is formed. It is applicable to the process of manufacturing. Thus, if a plurality of organic layers are stacked, functional separation of each layer is facilitated, and the degree of design freedom of the organic EL element with improved luminance and lifetime can be improved.

  Next, a substrate coating method according to a second embodiment of the present invention and a substrate coating apparatus for performing the method will be described with reference to FIGS. As shown in FIG. 9, the substrate coating method of this embodiment includes a fourth step of wiping off the coating liquid 20 adhering to the outer surface of the slit nozzle 31 between the second step and the third step. As shown in FIGS. 10A to 10C, the substrate coating apparatus 1 using this substrate coating method includes a wiping unit 8 for wiping the coating solution 20 attached to the outer surface of the slit nozzle 31. The wiping portion 8 is configured to be slidable in a direction along the longitudinal direction of the slit nozzle 31 along a slide rail 81 provided on the upper surface of the roller support portion 51. The width of the wiping portion 8 in the direction along the longitudinal direction of the slit nozzle 31 is formed to be substantially the same as the width of the connecting portion 34 as shown in the figure. In this way, if the wiping portion 8 is located immediately below the connecting portion 34, the wiping portion 8 can be prevented from contacting the slit nozzle 31 even when the roller support portion 51 slides.

  As shown in FIG. 11, the wiping unit 8 is in contact with the discharge port 30 of the slit nozzle 31 and wipes the periphery of the discharge port 30, and a pair of block bodies 83 that hold the wiping member 82. And a plate 84 for holding them. The wiping member 82 is made of sponge, rubber or the like. The block body 83 has an inclined surface 85 substantially parallel to the inclined surface 32 of the slit nozzle 31, and an opening 86 for supplying the cleaning liquid is provided. The plate 84 is slidably provided on a slide rail 81 provided on the upper surface of the roller support portion 51. The cleaning liquid after cleaning the slit nozzle 31 is preferably discharged to the container portion 54 in the roller support portion 51.

  Operation | movement of the wiping part 8 comprised in this way is demonstrated with reference to Fig.10 (a) thru | or (c) mentioned above. First, in the second step (standby time), as shown in FIG. 10A, the roller support portion 51 is disposed so that the roller portion 50 is positioned immediately below the slit nozzle 31. Therefore, when the second step is completed and the fourth step is followed, first, the roller support is performed so that the slide rail 81 is positioned directly below the slit nozzle 31, as shown in FIG. Slide the part 51. 10C, the wiping portion 8 is slid along the slide rail 81, and the wiping member 82 (see FIG. 11) is squeeged to the discharge port 30 of the slit nozzle 31, thereby discharging the discharge port. The coating liquid 20 at the periphery of 30 is wiped off.

  Note that the fourth step may be performed after the second step, and the first step may be performed without performing the third step. In addition, the fourth step may be performed after the third step and before the first step. This is due to the influence of the coating liquid 20 remaining in the vicinity of the discharge port 30 of the slit nozzle 31, and the coating film becomes non-uniform and is mixed with the coating liquid 20 in the slit nozzle 31 to contaminate the coating liquid 20. This is to prevent the cause, and the fourth step can be appropriately performed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. The control units (not shown) for driving and controlling the coating unit 3, the coating liquid feeding unit 4, the roller liquid receiving unit 5, the substrate transport unit 7 and the like described above operate based on predetermined software. The substrate coating apparatus 1 includes an operation unit (not shown) for inputting the type of the coating solution 20, the size and number of coating films to be produced, and the like. The software is constructed so as to optimize the driving of the coating unit 3, the coating liquid feeding unit 4 and the like in accordance with the operation information input by the operating unit.

DESCRIPTION OF SYMBOLS 1 Substrate coating apparatus 2 Coating liquid storage part 21 Inner accommodating part 22 Outer accommodating part 3 Application | coating part 30 Discharge port 31 Slit nozzle 4 Coating liquid feeding part 5 Roller receiving part 50 Roller part 7 Substrate conveyance part 70 Substrate 8 Wiping part

Claims (8)

A substrate coating method for applying a coating liquid on a substrate using a slit nozzle,
A first step of applying a coating liquid from the slit nozzle to form a coating film on a substrate that is intermittently transported;
A second step of waiting after the first step without applying the coating liquid on the next substrate;
Before the first step, including a third step of discharging the coating liquid to a roller portion disposed at a position below the slit nozzle from the discharge port of the slit nozzle with a gap therebetween,
In the second step, the coating liquid is discharged from the slit nozzle to the roller unit, and the amount of the coating liquid discharged in the second step is discharged from the slit nozzle in the third step. A substrate coating method, wherein the amount is less than the amount of the coating solution . The coating solution is stored in an inner housing portion of a double-structured coating solution storage portion having an inner housing portion and an outer housing portion, and fluid is injected between the outer housing portion and the inner housing portion. When the inner container is pressurized, the liquid is supplied to the outside of the coating liquid storage unit, and does not come into contact with the outside air in the process of liquid supply until the liquid is discharged from the slitter nozzle. Item 2. A substrate coating method according to Item 1. 3. The substrate according to claim 1 , further comprising a fourth step of wiping off the coating liquid adhering to the outer surface of the slit nozzle between the second step and the third step. 4. Application method. The manufacturing method of the organic electroluminescent element characterized by forming the film | membrane which comprises an organic electroluminescent element with the board | substrate coating method as described in any one of Claims 1 thru | or 3. A method for producing an organic electroluminescent element, further comprising forming a film constituting the organic electroluminescent element on the coating film formed by the substrate coating method according to any one of claims 1 to 4. . A coating liquid storage section for storing the coating liquid;
  An application part for applying the application liquid using a slit nozzle;
  A coating liquid feeding section for feeding the coating liquid without touching the outside air from the coating liquid storage section to the slit nozzle;
  A roller liquid receiving portion that slidably arranges a roller portion below the slit nozzle;
  A substrate transport unit that intermittently transports the substrate below the slit nozzle,
  The application unit discharges the application liquid onto the roller unit before applying the application liquid onto the substrate during the standby time during which the application liquid is not applied to the substrate, and the application liquid discharged during the standby time. The amount of is less than the amount of the coating liquid discharged from the slit nozzle before applying the coating liquid to the substrate. The coating liquid storage part has a double structure having an inner storage part and an outer storage part,
The coating liquid is stored in the inner housing part,
The fluid is injected between the outer housing portion and the inner housing portion and the inner housing portion is pressurized, whereby the liquid is fed to the outside of the coating liquid storage portion. A substrate coating apparatus according to claim 1. The substrate coating apparatus according to claim 7 , further comprising a wiping portion that wipes off the coating liquid adhering to the outer surface of the slit nozzle .

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